A sexual act involving two males. The first male gently cups his testicles with one hand, while using the other to lift the penis so as to have a space between the top of the scrotum and the underside of the the shaft of the penis. The second male then thrusts his hardened penis into this space. The first male releases his penis, creating a more tight space for the second penis to fill. The second male proceeds to fuck this space.

The first male may always opt to squeeze his entire package in between his hands, so that the male fucking the scrumdiddle may receive more pleasure.
Charlie: Hey Jim, wanna scrumdiddle after dinner?
Jim: FUCK YES I DO!
by Gay Jim January 5, 2013
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