Second heartbeat 

A thumping or throbbing expressed by the female genitalia during periods of sexual arousal, response, frustration, or climax. Described by many as being similar to a heartbeat

Just found out guys can feel your second heartbeat and I used to sit on my ex’s lap all the time. Time to drink the pain away

Second heartbeat by Sen. Kammy February 13, 2020

Second heartbeat 

The pulse that can be felt in a woman's vagina

Dude 1: Yo bro I hit her so deep I could feel her second heartbeat!
Dude 2: That's sick bro.

Second heartbeat by George_2 February 11, 2020

Second Heartbeat 

A powerful yet platonic connection between two individuals; often betwixt those with many interests and beliefs in common.

The term can be used in various ways such as the following:
'This is -name- (e.g. Sarah), she's my second heartbeat.'
'You consider HIM your second heartbeat? yolo indeed.'

Second Heartbeat by Antlette Du Fromage January 4, 2014