Circumcision Joke [nsfw]

A mohel (for those who don't know, a mohel/moyel/mohil is a Jewish person trained as a circumciser for the bris) is about to retire and calls his friend in to tell him the news. His friend said "Why that's wonderful news, you've spent many a year behind the knife, I bet you'll be glad to retire." "Yes, I am, and look at this. I've saved every foreskin from every bris I've ever done, all here in this ziploc bag," and he pulls out a enormous bag full of foreskins. "Well, that's, um, different, I guess.. but why on earth would you save all those?" "I'm going to take them to a tanner and have him make a keepsake out of them." Mohel goes to the tanner, has the foreskins made into a keepsake, and later sees his friend on the street. Friend says "So did you have something made with the foreskins?" Mohel says "Of course, the tanner made me this" and pulls out a brand new wallet. "But Mohel, the bag was so full! You only wound up with this small wallet?" "Well yeah, but if you rub it it turns into a suitcase."