I like when my guy finishes inside me, it's intimate and a turn-on. I've been on birth control almost constantly since I was 16, and don't ovulate regularly, so am less fertile already anyway. However, I use condoms as well with any guy I haven't established as having clean STD results, so those guys didn't/don't get to finish inside me directly, whether I'm casual or serious with them. And I'm much more careful about it now, because my ex either lied about recent testing before he was with me, or he fooled around on me. I'm betting both, because months after our breakup, one of his female friends informs me at the bar that he had been with her and at least one other girl during at least half of our relationship. Either way, I ended up positive for chlamydia when I got tested after our breakup [I always test between partners], and I know for a fact that I got it from him, because I was negative for everything on my test before I got with him. Anyway, I was disgusted and irate, got it taken care of, told him he needed to get his s.hit checked and inform whoever else he may have been f.ucking, and now I refuse to get rid of condoms until there are physical ON PAPER results showing me that the guy is clean. He screwed me over, but it's partially my fault because I should have demanded the evidence instead of just taking his word, because his word ended up not being worth much.
ANYWAY, when everything is completely safe and clean, particularly with a serious partner, I prefer that my guy finish inside me, whether it be orally, vaginally, or anally.