LMDH 

1) to laugh until your dick gets hard
2) to laugh at something so dirty and funny you get hard

Jake: look at this girl getting banged
Jake2: LMDH

LMDH by brilliantlywhite October 2, 2008

Lmdh 

Short for let my dick hang
Similar to: mind your business, give me room, and get off my back

1: where were you at 4am

2: back up and lmdh

Lmdh by Csah February 7, 2021