Some omegas in A/B/O fanfics have traditionally “female” or intersex genitals. A heatslit is just another term for the “vagina” of the omega. In some works however it’s a derogatory term for vagina. It’s typically used for males.
“Hey man did you see that omega just now?”
“Yeah?”
“Imagine how tight their heatslit is? 😏”
“…gross.”
“Yeah?”
“Imagine how tight their heatslit is? 😏”
“…gross.”
by Fanficdude July 10, 2022