Nullo

Class 1 Nullo - A man who has had his testicles removed (castrate).

Class 2 Nullo - A man who has had both his penis and testicles removed (smoothie).

Class 3 Nullo - A man who has had his penis, testicles, nipples and belly button removed (extreme smoothie - xsmoothie).

Class 4 Nullo - A man who has had his penis, testicles, nipples, belly button, fingernails and toenails removed (nullunx).

Class 5 Nullo - A man that has had his testicles, penis, prostate, seminal vesicles removed to prevent any sexual function and who cannot physically ejaculate. In addition, his nipples and belly button has been removed to prevent any sensitive parts of his body from being stimulated. His has had both his fingernails and toenails removed so that the end of his phalanges are smooth. (extreme nullunx - xnullunx)

Class 6 Nullo - A man that has had his testicles, penis, prostate, seminal vesicles removed to prevent any sexual function and who cannot physically ejaculate. In addition, his nipples and belly button has been removed to prevent any sensitive parts of his body from being stimulated. His has had both his fingernails and toenails removed so that the end of his phalanges are smooth. In addition his ears have been removed so that he has no protrusions on his body (unicorn).

After the man had sexual confirmation surgery, his dream was to become an xnullunx (the ultimate nullo).

Nullo by XnullunX November 25, 2018

Nullo

Males who have their genitals removed.

Mephisto is such a nullo

Nullo by Mephisto's dad July 25, 2003

nullo

man who removed his own penis

stands and unbuckles pants and drops them to his ankles, revealing a smooth, shaven crotch with only a thin scar to show where his genitals once were

nullo by rob nash July 25, 2003

nullo

a complete void of a man’s ability to ejaculate, due to extreme sexual activity

Annie was bragging to her girlfriends how she wore her boyfriend out last night…

”by the time I got done with Walter last night, he had nullo!”

nullo by ReginaandRay December 14, 2008

Nullge 

A Null Bulge - A type of chastity present in certain NSFW art in which the bulge of the subject is round, usually accompanied by a symbol of a lock. This is usually made of rubber, commonly latex, and stops the subject from cumming completely. Additionally it may heighten the subject's feeling of pleasure.
Commonly used in tandem with dronification.

Drone #975's Nullge has been installed. Commencing further testing.

Nullge by zoetbh December 4, 2021

Nullpo 

A Japanese meme, born in 2002 on 2channel, a Japanese text board. In Japanese it's spelled ぬるぽ. Whenever someone says it, the obligatory response is "gah!" ( ガッ). Became famous outside of Japan mostly because of the visual novel and anime Steins;Gate.

Okabe: Nullpo!
Kurisu: Gah!

Nullpo by oishiiii July 9, 2018

nutlock 

When you jizz, and don't clean up properly. After a while it dries and crusts up on your nuts.

Guy#1: Hey man, I was jerking it the other day and missed some on the clean up.

Guy#2: Ah, I hate when that happens.

Guy#1: Yeah, I had some serious nutlock later.

nutlock by JHE June 1, 2009