The mindless, meandering solo or song played by coffee-shop "jazz" acts. Especially referring to the solo bass player, trying to channel Jaco, with his 27 string bass and his $15 homemade CD with his goateed face on the cover, for sale at the counter.
Jane felt dirty with the gratuitous, self-indulgent jazzturbation going on right next to her in the coffee shop.
The act of watching your wife fuck her black, ripped, 6'5 lieutenant while you sob and use your tears to softly stroke your flaccid webbed penis.
Dragnar: "Don't be a cuck and jasturbate."
Conan: "But I owe it to my wife. She's been in countless battles out there, she deserves me to perform jasturbation."