Looking for a doujin i saw a long time ago, i remember that the plot was about a group of co-workers going for a drink to relax after work. it was all guys and 1 girl so naturally they all start fucking, it ends with the guys all cumming in a beer mug and the girl downing the thing saying "disgusting, another!" and all the guys telling her thats not possible.
pic NOT related but interesting fact none the less