The action of having sex with twins, much like a threesome.
I want to have a twinsome with Jack and Finn Harries
by parisssssssss October 23, 2012
Like a Threesome, but with twins and one other partner.
Look at those 2 twin blondes playing pool, think I'm gonna get me a twinsome.
by Jeff Delaney June 27, 2005