I know that a slut in theory takes any load, no matter what - and if this is in a dark corner of a darkroom, or with your ass stuck through a glory hole for anyone to take, fair enough.
Apart from situations like that where your contact with more that the man's cock may occur, do you have any limits - how dirty his cock already is, how dirty his ass is if you decide to top for a while, how smelly he is - more than a days worth of sweat, does his breath stink?
For me, if he was either clearly the worse for alcohol or was using anything stronger than poppers,I'd be out of there. Rimming a sweaty ass or licking sweaty pits could be a turn on - I have yet to reach a limit there!