on about 5 tries this was the best I could get going - the rest were even less good.

Stranger: talk
You: no
Stranger: you just broke the internet
You: No you did, with your face
Stranger: that's hot
Stranger: got any pics of your cock?
You: best I could come up with on the fly
You: You know, taking inventory of my reasonably sized photo collection, I can safely say there is not one photo of my cock in there.
Stranger: take one then
You: There are far more attractive subjects I'm afraid. I'm no enemy of my cock, I try to treat it well and all - but nah, no pics
Stranger: you do know that if you sent me a picture of your cock.....
Stranger: that would make you a fucking flaming faggot, right?
You: Hrmm. Most gay folks I know probably wouldn't send you a picture of their cocks either
Stranger: that sucks.
Stranger: how many do you know?
You: Well, there's no shortage of cock shots available elsewhere.
Stranger: got any links?
You: I think you could be up to your eyeballs in cock pictures if you so desired
You: I don't - but I think if you were to pick any search engine and say "Cock me up!" you'd be happy with the result
Stranger: lol
Stranger: you're funny
You: thanks
Stranger: i've got more people to go fuck with now. nice to meet you though.
You: You too. Good luck with the fucking with folks!

School's out for summer.  It might get better in September.  Maybe you can try back then. 

Yeah, definitely on life support.

Stranger: TITS OR GTFO!?
You: Is my choice to send you a picture of my breasts or leave? Just to be clear and all
Stranger: :O!
Stranger: Girl?
Stranger: Srsly?
You: Totally hot smoking GMILF
You: I'm like 90 years old, but my tits defy gravity
Stranger: :O KEWL!
Stranger: PICTURE OR IT DIDNT HAPPEN!
You: Really. We may need some lubrication for our inevitable rendezvous, but I've got plenty!
Stranger: ew..
Stranger: perverts!

You totally should have sent them the "Angry Squid barely wrapped in a towel" pic. Tease.