I guess any friends you're honestly afraid of knowing you should let them know "hey I did something stupid and am being blackmailed for sexual pics so just ignore any unsolicited pics from another profile about me"

If your friend still decides to be an ass and share it anyways you can at least have a message showing what a huge asshole they are for spreading it further

Post the dick pic before him. He will have no power.

Seriousness just block and move on its a side account anyways

Which is why it's separated to show representation for those genders