Yes.
MMF threesomes.
You've probably got to be at least orally bi (or gay, as some on here will insist) to really enjoy it. After the double blowjob you want to go for double vag - much tighter, incredible sensation, especially if the other guy cums while you're both in her. There are plenty of couples on AW who offer these services. Double anal best of all, but not many will do it.