A chav or any other male who is particularly interested in women's underwear, particularly the gusset region.
Mainly men who don't get sex a lot and like the smell of underwear
"Get out of my knicker drawer you gusset monkey"
"He was a right gusset monkey, he couldn't stop sniffing my crotch the dirty unwashed chav"
male that resides in the crotch of a sweaty skanky ho, usually chav
OMG chris is a right gusset monkey