(1) Any amount of jizz that successfully evaded detection post-ejac, but is discovered unintentionally at a later date.
(2) Anything so bad that its existence is comparable to that of left-over jizz/vaginal fluid; an exclamation of a situation's ability to evoke in you the feeling of finding dried semen someplace you hadn't expected it to be.
- Dude, what's this white stain on my hamper?
- Oh shit, I thought she caught it all last night. That's just my cumscuttle.
- Women's rights?
- Oh fucking cumscuttle.