In-Sync 

When you and your partner are having sex

"Hey Babe, we are totally In-Sync!"

In-Sync by an eddie September 21, 2020

In sync 

When two or more people say the same thing at the same time.

Jane: I wanna do something!
Billy: Let’s go do something!
Jane: In sync!

In sync by RFreshton September 30, 2017

in sync bb 

when you and your "friend" wake up at the same time.

"just woke up"
"me too, in sync bb"
"😍 lets go"
"now we can have sex"
"sure"

in sync bb by notcassie October 14, 2021

In sync bb 

A joke in the Dream smp fandom, more so common in the Dnf fraction of the Fandom, where Georgenotfound and Dream(wastaken) woke at at the same time and texted each other.

The texts were read out loud by dream on stream, and has been clipped and viewed by people many times.

Dream= in sync bb
Now we can have ***

George= sure

In sync bb by Proxwashere September 13, 2021

pumping cock in sync 

usually performed while watching porn, but also applicable while watching live sex at a party

the act of matching the penetration depth of cock in observed fornication to the depth of one's own cock in one's own hand or other cock stroking device

balls deep in observed fornication pull hand down to match either to base of cock or to the limit of stimulation of hand

boxers all the way down, lube ready, porn site loaded and porn playing, reality melts away pumping cock in sync, usually jizzing before video ends

repeat until unable to get hard again in lieu of fornicating.

pumping cock in sync by pumps alot April 28, 2012

insyncex 

In sync exercise.
Two lovers coming together to "do life" step by step in sync always watching each others back helping catching giving taking. gradually getting better.

"I want to do the insyncex with you."

insyncex by Krkič December 4, 2021

Insynctomatic 

When you are so in sync with the homeboys that no one else can jump on your wavelength because the symptoms of this ultimate duo are asymptomatic.

Damn homiebear, we insynctomatic fr fr.

Insynctomatic by Menacing Magnet Mandem May 2, 2022