I really think you should be on PreP if you're going to take anon loads. From everything I've read and heard it's just a matter of time before you lose the game of Russian Roulette.
I've had guys tell me they're poz as they're shooting but I always assume they are anyway if they're having random bareback sex. One guy actually got turned on when he thought he was pozzing my ass. After he came I suggested that, while he may be poz, he has no idea what I may have, which freaked him out a bit. But hey, it was true, I'd been pounded by a lot of anon guys that day at the sauna.