alphabetically... 
otherwise... Here's a random list to tide you over while you make your mind up
It appears through the opposite wall of your own cubicle. You poke it in an out several times in disbelief, shrug your shoulders and then give yourself a handjob and facial anyway. 
The lurid set of a Japanese gameshow where the crowd inexplicably applauds when your cock appears. The host shouts the words "SUPERU COOL!" and daubs the head of your member with silver paint, prompting more applause.
A vast auditorium, perforated with thousands of other glory holes, through which poke cocks of every colour, length and girth. In the centre stands Richard Littlejohn, who has just realised that the auditorium has no doors, and he must suck or starve
The set of the Moomins.
Another cock, traveling towards you at exactly the same speed as your own. The two todgers meet japs-eye to japs-eye in the glory hole's shaft, 'kissing' each other like Russian politicians at a military parade.
A parallel earth, many magnitudes smaller than our own, that launches an 'Armageddon'-style space rocket to blow up your glans, manned by a tiny Bruce Willis, Ben Affleck, and Steve Buscemi.
Disappointingly someone hangs their donut on your manhood while they take a dump.
Stephen Hawking's cheek, but there is nothing he can do about it apart from flick his eyes up and to the left over and over again as all the semen from a great many men spatters his paralysed face.
Patrick Moore playing a frenzied xylophone piece. He pauses, looks at the purple helmet now staring him in the face, tuts and then continues playing.
Your dad
An Amsterdam-based Jewish family, hiding from the Nazis.
A room where a woman scratches "Help - we've been locked in for 3 years" into your foreskin with a nail. Angered at the pain and lack of fellatio you wee through the hole and leave
George Bush in his oval office. Confusion over the desire to touch it and the knowledge that he really shouldn't in his position means he is rendered immobile for about half an hour. You can't quite reach the red button with your cock though
Lloyd Grossman, describing the home of a minor celebrity in an ironic, Bostonian drawl, who mistakes your member for 'a witty coat peg, in the shape of a pink peeeriscope'
The mind of John Malkovich
A cliff face, over which tumbles a cartoon Coyote. It grabs your stiff John Thomas, saving itself from plummeting to its doom. But, as you lose your erection, its paws slowly slip down your soft, greasy shaft, and the Coyote goes into free fall...
The ugly woman from "Porky's", who grabs it, saying "I know you're Tommy Turner, I recognise that tallywhacker" - whereupon you point out her mistake. Minutes later you're chuckling about this case of mistaken identity over a nice cup of tea.
Acker Bilk, who grabs it and knocks out a show-stopping version of 'Stranger On The Shore' while he defecates.
Narnia. Reacting to the cold, your cock becomes very small and is a main focal point and great source of amusement for the chattering woodland community, for many weeks to come.
The Large Hadron Collider
The end of Schindler's List where Liam Neeson is breaking down in tears on the train track. The director shouts "CUT! Cock in", as the black and white yogurt-spitter ruins the mood of the scene.
The round window on Playschool, one Wednesday afternoon in April 1973. Time extradition and trial for mass indecent exposure follow, but as it's 1973 you just get fined £25, and return to the present day sadder but wiser.
A miniature guillotine.
A hasidic jew who opens his eyes mid prayer to find his lips not kissing the sacred stone of the western wall but your filthy goy cock.
A multi-holed tree stump, with the green bloated scorpion-thing from Flash Gordan waiting for you.
a class of nursery school children, who all burst into tears.
A grotty motel where Victoria Principal's taking 1 up the chuff from Phil Donahue while practicing lines for a cameo in a Murder She Wrote Movie playing a faded star reduced to turning tricks for obsessive fans & is in the frame cos its convenient
A mincer.
The set of Cock Cam LIVE, hosted by Kate Humble and Bill Oddie on BBC2.
"Go on, Bill," purrs Kate as she dabs jizz from the corner of her mouth, "Your turn"
A tobacco auction.
Marie Antoinette's great-great-great-great-granddaughter with a G-willy-tine
