one-eyed spitting cobra 

It's pretty much your mom's favorite animal. Indigenous to the trousers of the mutant and bred for its skills in sex. Usually directs its venom at the eyes when agitated.

The one-eyed spitting cobra is an endangered species. Only one is known to be left in existence.

one-eyed spitting cobra by the mutant February 8, 2007

one for Ron 

A way of taking two of something when you're only being offered one. As seen in the Mike Leigh film 'Meantime' (1983).

"I'll have one for now, and one for Ron...later Ron".(Later on)

one for Ron by World of Weird July 10, 2003

One in seven billion 

A better way to say "one in a million" because there is around seven billion people in the world and you believe that he/she is the one for you.

May: How much do you really love me?
John: I love you very much?
May: Do you think I am your one in a million?
John: No, you're my one in seven billion. Will you marry me? -shows ring-
May: Yes!
Then they got married and had kids.

One in seven billion by World of Wordcraft April 18, 2016

one of our own 

Part of a chant used by football fans to describe a player who grew up around their area as well as rising through the ranks of the club. Notably used in Tottenham Hotspur fans' chant for Harry Kane

Hes one of our own, hes one of our own, Harry Kane, hes one of our own

one of our own by Sozzai September 21, 2016

one third rule 

A restriction for anal sex invented by director Kevin Smith. When the penis is longer than 6 inches, you can demand that it is only inserted 1/3 the way in.

His cock was so long that she demanded the one third rule!

one third rule by JohnnyFlash71 October 16, 2010

one in the oven 

a woman who is pregant

tracy that silly old sour faced tart shes got one in the oven

one in the oven by grumpyboy September 26, 2005

One platoon wonder 

the most knowledgeable part of a NAVY S.E.A.L.s career the moment he returns from his first deployment when he now knows everything about being a S.E.A.L. and needs zero fucking guidance from anybody at all regardless of their rank or experience level.

Thank god we got so many fucking one platoon wonders. telling us what we do. it is just impossible to think how we ever fought the war without them. Lets all grow beards never cut our hair and tell the C.O. to go fuck himself. It must be the right thing to do I mean thats what the one platoon wonders want.

One platoon wonder by captain fucko February 6, 2010