Many times
On a long weekend away from college many years ago, went to a college roommates house.
The weed was plenty and several of his old H.S. friends came over to party. As the night winded down no one was leaving. My sleeping arrangements ended up being with my roomy and his girlfriend on a queen bed... woke up an hour later to a BJ... which evolved into MFM spit roast among other positions...
Quite a few

Quote by Meggsy
Frequently. Living with another woman and us both having male friends - it happens - and we ALL enjoy it.
Yes we had many 3sums as students with my gf and her flatmate. She had a number of boyfriends so my gf and I enjoyed the variety. Three can truly play as one. It’s been my favourite form of sex ever since.
With two women only a time, when I went oftenly to a downtown whorehouse. I still remember that: a gal- 1000 pesos, two gals- 1500. The experience was very good, despite I had an appalling performance, even when they were both two true goddeses.
With guys I have it more oftenly, on a gay sauna I visit.
The only thing is unconvenient is the difficult to concentrate on give pleasure and get it from more than a partner.