Simultanal 

Simultaneous anal. Generally it involves two males, one of which inverts, and they both push their erect penises downwards, and then back into one another as to simultaneously penetrate one another.

What's simultanal? Oh, it's the 69 of butt sex

Simultanal by H$izzleM December 14, 2020

Simultanatelephobia 

The fear of trying to call someone at the exact moment they are trying to call you, and thus being irrationally afraid to pick up the phone for fear that the party trying to reach you would receive a busy signal. This mental illness was very common before the advent of "call waiting".

The nervous bitch wouldn't let anyone use the phone because of her simultanatelephobia.

Simultanatelephobia by Alan V. February 19, 2005

simultaneous trumpfinger 

A now popular occurrence describing the phenomenon of a group of people flipping an emphatic bird at the same moment, often at the mere sound of 45’s voice.

Simultaneous trumpfinger, while watching the news, has become a family bonding experience in our household.

simultaneous trumpfinger by Dr Bunnygirl September 15, 2020

simultaneous equation 

equations involving two or more unknowns that are to have the same values in each equation.

If an equation has two unknowns, such as 2y + x = 20, it cannot have unique solutions. Two unknowns require two equations which are solved at the same time (simultaneously) − but even then two equations involving two unknowns do not always give unique solutions.
This gives us a 'simultaneous equation'

simultaneous equation by rieazen September 9, 2014

simultaneous snoregasm 

Profoundly peaceful sleep shared by a couple after lovemaking.

Feeling what he knew would be her final orgasm of the night, he joined her, in perfect sync, and they fell into a state of simultaneous snoregasm, neither of them stirring until sunrise.

simultaneous snoregasm by Monkey's Dad February 27, 2020

simultaneously 

adv. - to do at the same time.

I masturbate and watch porn simultaneously.

simultaneously by Masterion August 2, 2011

Simultaneous release 

when one concurrently urinates and defecates; referenced in the song "Dani California"

I would sure rest in peace after a simultaneous release.

Simultaneous release by prague1 June 30, 2006