PUKE SEX is just a term refering to sex between two people that most likely have been drinking alcohol (beer/wine/anything) to the point that they are acticing really skanky and dirty, maybe they have puked once already that night. these two people hook up and have sex. this gross, drunk, regretable sex is called "puke sex".
PUKE SEX is a term for the sex that is had by the two drunkest people at the party. sloppy, no love involved, maybe some puke breath, puke on the bed, or puking during the act of sex...and continuing on.
"Jimmy and Sara were so Ham Boned last night. I caught them having Puke Sex in garage. Now the garage smells like Bontch and their are stains all over the floor."