Poor Jasper. Chris probably thought the whole thing was funny (part of his to be later revealed backstory, not an assumption of how other androgynous-looking people would feel in that situation), but Jasper would have been all kinds of embarrassed having to explain that there's been a wee little mistake...
Betters, you will notice your karma points being adjusted over the next few days.
Side note: Forumites, please stop starting threads for the weekly comic. That is a task for Lore or I, and we use that first post for our comments or explainations for that week's comic.
An even more spelled out explaination than Lore's:
Jasper asked Chris out on the assumption that since "she" told Val that she doesn't swing that way, "she" is a woman. Chris accepted the invitation on the assumption that Jasper was attracted to him as a man.
Jasper discovered, after a successful date that led to some mild intimacy, a piece of equipment generally not found on those of the female persuasion, which left him in the position of explaining his misconception and the subsequent ending of the date. At which point he went to the pub to tell his tale of woe, which Val found hawt.
Which all goes to show that making assumptions can lead to socially awkward mistakes.
In Summary: Those thinking that Chris was a woman are wrong, those thinking that he is a man are correct, and the person who suggested that he didn't like the ladies was spot on.