double barreling
{man says to neighbor boy} hey, you interested in having my wife go double barreling on us? boy asked, whats that? the man makes jerk-off motions with both hands
when a girl gives simultaneous handjobs to two guys
"{man says to neighbor boy} hey, you interested in having my wife go double barreling on us? boy asked, whats that? the man makes jerk-off motions with both hands" What is the definition of "double barreling"?