Strecthgasm is a combination of two words. Strect and Orgasm.
Stretchgasm is the feeling you get if you wake up in the moring and you stretch. You feel go and your muscles get relaxed. It feels like an orgasm but more on the backside.
Stretching for staying in onespot for a long time.
Person: *strecthes*
Person: Damn what a stretchgasm!
a feeling of utter bliss that happens when you're lying on your floor after doing something particularly exerting, when all your muscles relax and you could just pass out right there. similar to a bedgasm, but on the floor. sometimes called floorgasm
girl: "uhngggg...."
guy: "hey, you okay?"
girl: "yeah i'm fine, i'm just having a stretchgasm, don't mind me."