Globules or strands of stray cum which might have travelled further then you thought & thus don't get cleaned up, which once dry look it / resemble a slug!
Ken "I had a good wank the other day in my mums room, I thought I'd cleaned all the cum entrails up but a few cum slugs had formed on the wall which I hadn't noticed!!"
Frank "what happened, did you mum find them?"
Ken "yeah & it wasn't the first time she had found my cum slugs, so I was in deep trouble!!"
A spooge-filled condom, usually haphazardly tossed upon the floor.
Hey did you remember to uncuff the clow-GOD DAMN IT I'VE STEPPED ON A CUMSLUG.
Noun, a thick white glob of semen that resembles a slug.
I blasted her with a cum slug in the face and marveled at how it appeared to crawl toward her chin.
The residue dripping out after having anal sex and letting your partner ejaculate into your rectal passage
Max: Mmmmm, I've got some drippage! Must be a cumslug!
can be used as both a positive or negative phrase...
Positive: 'Wow...check out that piece of ass, shes a real cumslug'
Negative: 'I can't believe you shagged that greasey minger you cumslug!!!'