We've been into mfm fun with a guy we know for 5 years off and on. Very infrequently at first.
We're not pros at this, we aren't swingers. We are comfy with out friend but it's still weird and awkward for me, much less so for my wife.
While we're messing around with him, can be 3 or 4 hours, it's incredibly exciting but after we both have...what have we done...feelings.