In my dorm, there's a really popular game called One Night Werewolf, which has a really long explanation of rules that I won't go into here, but involves giving everyone a card and then having them participate in the game in a certain way depending on what card they get. During the game, everyone's eyes are closed, and the roles get called out in order by card. I came out to the core group of people who usually play that game by saying "Technically, this should be me all the time" when the ace was called.
Whether someone is comfortable with sexual jokes may not have much to do with whether or not they’re asexual. There are a couple of instance in which it could, though:
They’re repulsed not only by sex but also by conversations about sex
The jokes are dependent on the underlying assumption that everyone wants sex