Colloquially in English it is not uncommon to refer to another human being as a genital. In such cases there is a sliding scale of offensiveness ranging from the not so offensive to the very offensive. The correct use of the right colloquial on the Sliding scale depends on the actions of the Human in question. It is important that you use the right one at the right time. The use of these colloquials is often used for humorous effect but can also be used in anger and exasperation. It is almost always the case that you don't use the colloquial in front of the person you're referring to unless of course you'd like to partake in a violent conflict.
Willy
1. The male sex organ.
2. A human usually a man who has inadvertently done something stupid.
"I think I've just put salt in my Tea."
"You're such a Willy."
Nob
1.The male sex organ.
2. A human usually a man who has done or said something stupid.
"Mike's crashed another car."
"Bloke's a Nob isn't he."
Fanny
1. Female genitalia.
2. A human usually a man who has said or done something stupid for comic effect.
Pussy
1. Female genitalia.
2. A person who is exhibiting signs of fear, non-committal and needs goading.
"Jon is such a pussy he's actually scared of vagina."
Penis
1. The male sex organ.
2. A person usually a man who has said or done something stupid for reasons other than comic effect.
Pee hole
1. The hole on the tip of a man's penis.
2. A human usually a man who has said or acted selfishly.
"Ryan, you pee hole, you ate the last cake!"
Minge / fanny flap
1. The fur covered labia of a woman's genitalia.
2. A human usually a man who has said or done something maliciously.
Dick
1. The male sex organ.
2. A human probably a man who behaves maliciously from spite.
Twat
1. Female genitalia.
2. A human usually a man who has taken their spiteful and malicious behaviour too far.
Scrotum/ Scroat,
1. The sack which holds the testis.
2. A human usually a man who has taken their spiteful and malicious behaviour too far. So much so that you wish them ill.
Ballsack/ Ball bag
1. The sack which holds the testis.
2. A human usually a man who has taken their spiteful and malicious behaviour too far. So much so that you wish they would severely hurt themselves.
Bell End
1. The bulbous tip of a penis.
2. A human usually a man who has taken their spiteful and malicious behaviour too far. So much so that you wish you could severely hurt them.
Arsehole
1. The Rectum.
2. A human usually a man who has taken their spiteful and malicious behaviour too far. So much so that you wish them dead.
Cunt
1. Female genitalia.
2. A human usually a man who has taken their spiteful and malicious behaviour too far. So much so that you wish them a slow and lingering death.
It is important to note that some of the above colloquial are also affectionate abbreviations of common names. You must use context and tone of the conversation to decide if your friends are talking about a man called Richard or a man who is a Dick.