I have a slightly different perspective from being in a poly family, two guys and three women, who are joined by another guy sometimes to play. This is about how often within our closed group, not with new partners. All three girls will take anal from two of the guys; hubby doesn't like it and his dick's too big around (for my bum anyway). We women do anal about once per week and DP about once per month. Lora and Clair enjoy and can come from anal alone; I can't, it has to be part of DP to get me off. The other thing is that although none of us are shy and will lick a dick or each other's pussy after sex, once a guy puts his dick in anyone's ass, playtime ends when he's done. So it is inherently self-limiting.