"Thats what she said" is getting old. So the new phrase "Like my penis" or in more appropriate words, "Like my wiener" was established to take its place. It's used in a similer way to "Thats what she said"
Whenever someone says something that could also be referring to a penis, you say, "Like my penis"
Girl#1- Oh my gosh, this test is soooo hard!
Girl#2- LIKE MY PENIS!!!!!
Girl#2- LIKE MY WIENER!!!!!