at half mast 

where you had a throbber, and then has died down, but is still not gone flacid, and is still erect, but has just lost most of the inflation, giving the impression of a pencil dick, but you've just not got a full-on boner.

i was having a wank the other day, and then i heard a noise, but then when i went back, i was at half mast

at half mast by Shaun-e-e-e August 25, 2010

flag at half mast 

semi-erect penis, hollywood loaf, not ready for action

Drinking all night put the flag at half mast, and Rob could not perform.

flag at half mast by elvette July 21, 2006

Sailing at half-mast

A partial erection.

I’m trying to get it in, but I’m sailing at half-mast.

Sailing at half-mast by Red Bastard July 4, 2020