|1.||the dusk tusk|
To get a boner when incredibly relaxed, for no apparent reason. Usually occurs just before you go to bed.
The temporal opposite of a morning glory
Man, I'm so sleepy. Oops there goes the dusk tusk. Time for bed.
Mum: Jonny, time for bed! What on Earth is that in your pants?
Dom: Oh, don't worry ma, it's just the dusk tusk, I'm real sleepy.