Refers to the act of while you are receiving a "deep throat" the executor reaching around and sliding a finger deep into the anus of the lucky recipient. With the finger completely immersed in the anus and the penis deep into the throat the executor then gargles as to stimulate the penis with their tonsils. Making a noise not unlike Chewbacca mid orgasm!
"Got very lucky last night...met a girl and had the best Treble T...she is a keeper!!