Previous in this series:
Part 9 - Utility Poles and Masts.
Part 8 - Crown of Thorns.
Previous Series - Crucifixion – The Bodily Support:
Part 10 - Humiliations.
Three Men Impaled.
Source - Russian website, not known.
(Kudos for this image and info below to Mr. P. Bahnen)
In this woodcut engraving, one of the impaled men, whose face is visible, is depicted smiling. The smiling victim is the only one who is depicted in detail. So he easily could have been recognised, if this were a real person whom the artist wanted to depict. Clearly, in my opinion, a mocking of the executed. For the uncensored version, click here.
Source - Britam.org.
This is an ivory engraving from ancient Israel, showing what appears to be a military procession or a return march from battle with spoils of war. Note here the captive Israelite or Canaanite slaves, naked and bound, exhibit a look of a slight excitement in their faces and engorgement of their penises. In reality the bound, exposed slaves would experience shame and humiliation but the a member of the victor nation wanted to get a message across that these male slaves are now considered "effeminate:" suitable, ready, willing and even horny for sexual exploitation, despite Levitical prohibitions to the contrary.
Source - infotdgeova.it
For a better illustration, click here.
And in crucifixion, the mors turpissima crucis, the humiliation is ultimate. In the Puzzuoli Graffito above, the subject of the crucifixion is shown riding an upright thorn, i.e., an acuta crux, a.k.a. a sedile or cornu. When the subject hanged down, he* also rested on the horizontal beam itself shaped like a horn, unintentionally or deliberately resembling an uncircumcised phallus.
* Some or most scholars think the subject is a woman. The strong V-shape of the upper torso, narrow hips, and even what appears to be the outline of a man's erect genitals at half-mast below the limits of the left leg, indicate otherwise (for clearer evidence click here).
In a nutshell, masculinity in males in the ancient world wasn't determined if he was gay or straight, but whether he was a top or bottom, and whether he had complete control over his body or not. And even then it wasn't that simple: males of sufficiently high status to be considered men had to keep up appearances. In other words, they had to be "tops," they had to be impenetrable, invulnerable.
"...Walters makes a crucial distinction between 'males' and 'men': 'Not all males are men, and therefore impenetrable.' In particular, he refers to the special nuance of the term vir, which 'does not simply denote an adult male; it refers specifically to those adult males who are freeborn Roman citizens in good standing, those at the top of the Roman social hierarchy -- those who are sexually impenetrable penetrators'" 
"...[H]egemonic concept of gender in the ancient Mediterranean world is not a reification of anatomy but its relativization of anatomy. We are presented... with a hierarchical gender gradient or or continuum..., in whose middle ranges masculinity begins to shade almost imperceptively into femininity, and vice versa, so that swift slippage from a more manly to a less manly status is an ever present possibility even for the socially advantaged male subject. 
And so back then a male who was considered a man and was perceived as less than fully masculine, especially if he was rumored to be a "bottom," even more so if it was proven, was reproached and even even referred to by a woman's name or title, as in the case of Gaius Julius Caesar, who was called "every man's woman," the "Queen of Bithynia" and many other humiliating terms that cast assertions on his masculinity as well. He was also the one of whom Nicomedes was called his paramour (actually the Latin is ruder: the term for paramour is pedicator: fucker.) 
And even when there is no cause to look askance at a man because someone has cast assertions on his sexual invulnerability, other kinds of vulnerability such as a surrender in battle to the Romans will earn him a feminine epithet. This is what happened to the last of the Hasmonean kings of Judea, Antigonus, when the siege of Jerusalem in 37 BCE: as the Roman soldiers were making mincemeat of the populace, regardless of age, disability or sex, Antigonus walked down from the citadel to the Roman commander Sosius and fell at his feet. Sosius' response? He laughed at him uncontrollably, called him by a feminine version of his own name (Antigone / Antigona), and bound him in fetters. 
And so in Roman crucifixion, when the condemned criminal, already perceived by society as sexually irregular, even a "gender outlaw" , has no control over his own body, is travelling up and down a "safe" (relatively short, blunt) impaling stake while performing the compulsory dance of the cross, he would inevitably be viewed as effeminate, womanish. And spectators who scratch out graffiti memorializing the event, they just might -- or probably would -- inscribe a woman's name over the illustration.
And this is why Cicero, in his Second oration against Gaius Verres, former Proconsul of Sicily, had this to say about crucifixion of Roman citizens:
Facinus est vincire civem Romanum, scelus verberare, prope parricidum necare; quid dicam in crucem tollere?"It is an offense to bind a Roman citizen, a crime to scourge him, almost treason to put him to death; and to crucify him: what can I say?"Cicero, In Verrem, 2.5.169-70
And then there is the Senatus Consultum de Cn. Pisone Patre, which refers to a trial of one Calpurnius Piso in 20 C.E. by the Roman Senate for, among other things, crucifying a centurion who was a Roman Citizen. If I have my facts straight, he swiftly suicided because of the scandal he caused by this and his other actions.
49 perspecta etiam / 50 crudelitate unica qui incognita causa sine consili sententia plurimos ca / 51 pitis supplico adfecisset neq(ue) externos tantummodo, sed etiam centorionem / 52 C(ivem) R(omanum) cruci fixisset;49 Also evidenced /50 was the unexampled cruelty [of a man] who had inflicted ca- /51 pital punishment on many without their cases having been heard, without recommendations of his advisors, and had not only non-citizen soldiers, but also a centurion /52 [who was] a Roman Citizen, crucified;Senatus Consultum de Calpurnius Piso Patre, Col. II (Copy A)
And Seneca tells us the reason why Roman authorities should not ever crucify Roman citizens, ever (although he never came out and actually said they shouldn't), when he quotes the poet Maceneas and upbraids him for writing "such turpitude of effeminate verse" (Ep. 101.13):
'Tu vero,' inquit, 'me debilites licet, dum spiritus in fracto et inutili maneat. Depraves licet, dum monstroso et distorto temporis aliquid accedat. Suffigas licet et acutam sessuro crucem subdas.' Est tanti vulnus suum premere et patibulo pendere districtum, dum differat id, quod est in malis optimum, supplici finem? Est tanti habere animam, ut agam?" 'nay,' he cries, 'you may weaken my body if you will only leave the breath of life in my battered and disfigured carcass! maim me, if you will, but allow me, misshapen and deformed as I may be, just a little more time in the world! You may nail me up and set my seat upon the piercing crux*.' Is it worth while to weigh down on one's own wound, and to hang racked-out on the gibbet**?"Seneca, Ep. 101:12* acuta crux, that is, a pointed upright stake to sit on.** patibulum, i.e., the overhead transverse beam that is set on the main post.
Seneca knows what's going on in a typical Roman crucifixion, even though he states in his Dialogue 6 (De Consolatione 20.3) that there are exceptions, or different means of suspension in different countries, or he's describing multiple tortures in a typical crucifixion.
Video istic cruces non unius quidem generis sed aliter ab aliis fabricatas: capite quidam conversos in terram suspendere, alii per obscoena stipitem egerunt, alii brachia patibulo explicueruntOver yonder I see torture-devices*, not just of one kind but differently made out of wood by others: some suspended with the head turned toward the earth, others drove a stake through the privates,** others stretched the arms out along the crossarm.
* cruces, usually translated crosses, but here should read torture-devices like suspension stakes, frames or even trees that killed a man by means of torture. And when Seneca says they were made "by others," we might be able to assume that he means, "not by us Romans (usually)." Of course the epigraph above shows that the typical Roman crux in his day was a combination of all three. A tri-crux, if you will.** drove stake through the privates": alii per obscoena stipitem egerunt, usually this is interpreted to mean through the genitals but could also mean "through the excrements," i.e., the anus, which is also a private part and in fact the most private.
Conclusion: Throughout history, people would insult captives and publicly punished criminals. The more shameful or humiliating the punishment, the worse the insult. And the typical Roman crucifixion was a shameful, humiliating, sexually charged death of state rape, as humiliating a penalty as can be which just was not supposed to be done to a Roman citizen. And due to the nature of the penalty, where the condemned criminal was going to die penetrated and on display, people made it worse by heaping insults on him.
 Stephen D. Moore & Janice C. Anderson, New Testament Masculinities, p. 70
 Suetonius, Lives of the Twelve Caesars, Julius Caesar, chapters ii, xlix, lii.
 Moore & Anderson., p. 18.