A girlfriend with an absurdly high sex-drive, which initally seems great, but then you realise it's far higher than yours and you can barely keep-up, you can't sleep, you've no energy, you feel like death and STILL SHE WANTS MORE
v. A person fucks like a fiend.
adj. Some who is too ugly to fuck
v. I tried to stay with it all night, but she was a fuck monster and I dried out.
adj. Look at Felix, he knows she aint looking at him, he's a fuck monster.