What is Segma?
1.
a classic misspelling of the word
illiterate A:
huhuh... hey like... wot's the name of that cheesy stuff i got around my bellend all the time?
illiterate B:
uh... uuuh... that would be like... SEGMA! huh-huh-huh.
See
2.
The cheesy substance that forms underneath the foreskin of a penis.
"No way am i going down there, look how much segma you have!"
See