It's a variation of a blumpkin. Instead of a chick blowing you, she shits on your balls. Then, when you fuck her, your shitty balls slap o n her ass and put it back.
This bitch was riding me on the shitter and she shit on my balls, so later I pounded her missionary and hit her ass with a return to sender.
After ejaculating into another person (creampie), the sender the proceeds to perform oral, thus taking back the dropped package.
He couldn't last, but he totally owned that return-to-sender to make up for it!
When you inject semen into your balls through a heroin needle
Hold on baby, I'm about to Return To Sender