Other. Grown children LIVE in my home, so we can't very well not have sex. We don't on the rare occasion that my mother is here. EW.
When we have overnight guests I usually prefer not to. (We don't have overnight guests as often as we used to, but especially around the Holidays, I don't like people driving while under the influence, so we usually request people stay. We had one friend, years ago, whom my husband would take the keys from as soon as he arrived, as he had no ability to say, "Enough.") I can't relax if I know someone might hear, and I think it's a bit rude. If it's only one night, we can wait until they go home. Sometimes My Man wants a quickie (he doesn't have the understanding, sometimes of what is socially appropriate) and I'll just have the quickie, but not attempt an orgasm. I make a LOT of noise, and I just think it would be rude.
Our friends have a pretty good idea we are sex maniacs, I don't need to illustrate it for them.