Blake Griffin -- HUGE PENIS ... Says Fat Jewish

Blake Griffin's penis is like a "Pringles can made of flesh" ... so says a dude who would know, The Fat Jewish ... who got up close and personal with Blake's dong during a game of mini-hoops.

The Instagram star says the two hooked up for an intense game of 1-on-1 ... and as TFJ put it, "The next thing you know he was doing a monster jam on me and his package was literally in my face."

Mr. Jewish added, "Also, for anyone wondering, yes I could feel the outline of his d*ck, dude has a Pringles can made of flesh in his shorts."