phantomfinger 

the act of inserting ones middle finger into the anus of a female while she and another man are engauged in intercourse in a lake.

Arkady gave her the phantom finger last night at the lake.

phantomfinger by sasquatchdu May 8, 2003

Phantom finger 

When In a pitch black room with a woman, you proceed secretly shove a finger in the woman’s vagina and in a low ouch voice say “phantom finger”

I gave this girl the phantom finger last night.

Phantom finger by B3rry McC0ckiner April 18, 2022