Took my receipt to the sperm bank so I can get this comeback.
Sperm Bank Return
Explanation
Explain Bear
Alright, listen up, you knucklehead. The joke is that the dude wants to return his sperm to the sperm bank, just like returning an item to a store. The "comeback" is a double meaning - a witty retort AND getting his sperm back. Ha... ha... Dumbass.