Your friend is terribly awkward (they say it's their autism, but you think all the time they spent reading dinosaur encyclopedias instead of playing with friends also didn't help) and they're venting to you about how they haven't had sex in SOOO LONG.
You being the excellent friend you are offer to help out!
When they let you know they're ovulating and aren't on any birth control rn, you're happy to change your plans and eat out their tasty boyholes while they encourage you with moans and some dirty talk.
You're such a good friend!