My question then is "Why would you not?!?" I mean, if you're having a hookup or one-night stand as opposed to someone you're aiming to woo as potential BF, what else are you expected to do? Unless time and/or location constraints indicate it should just be a quick blow job or jack off. But if you've planned this in the least or just picked up a guy in a bar or something, the idea is kinda in place that there will most probably be fucking.
I'm not sure if this was a rhetorical question or if you're actually wondering, but I'm leaning towards the latter. My answer is threefold:
1) I just don't do hookups generally speaking. I don't enjoy the extensive calculation of risk that one has to do with a hookup. The one time I had a proper hookup (had sex on first meeting from a hookup app) I failed to properly calculate and picked up something. And this was after being sexually active for nearly a decade, so it's not like I was totally green and naive. It also doesn't satisfy my preference for intimacy and I find it difficult to process emotionally. To top it off it's pretty awkward; I'm not one who's generally able to have comfortable interactions with new people.
2) I ascribe a very high degree of intimacy and "soul connection" to sexual intercourse. That doesn't mean that I refrain from engaging with it save for marriage, but it does mean that I shy away from it unless I know and trust someone and feel we have that connection.
3) Over 95% of my experiences of intercourse have been without a condom. That's because they've all been with my ex. We used them a few times starting out the relationship and then discarded them once trust was developed. I haven't had to use them hardly at all (there was one time after we broke up) in the past several years. And I remember them being pretty unpleasant, so I'm not eager to jump back into a situation where I have to. Not to say I wouldn't if it came to that, but it is another factor that's leading me to shy away from more casual anal sex opportunities.
So, with respect to #'s 2 and 3, even when I do occasionally fool around with a friend, so far I've avoided having it escalate to engaging in intercourse.