SDMF 

Scroll Down Mother Fucker

If you SDMF and read the email
Below you would see the answer to your question.

SDMF by Irocnibroc February 20, 2019

sdmf 

Small Dick Mother Fucker

When you send a dick pic and they tear down the size of it.

Dude sent a dick pic to this chick, who savagely replied with "sdmf pass".

sdmf by Musky Mitten March 6, 2020