Top definition
When ones penis is no longer erect, possibly either after blowing ones load, or just losing an erection. A semi-boner is often used for playfully slapping ones friends in the face while they sleep for a hilariously good time.
To try and piss my friend off, I got a semi-boner and helicoptered it around in his face.
by BLICK12 April 23, 2006
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The vengeful act of crapping on a lover's chest while they sleep.

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2
A semi-boner is when a man's penis is no longer erect after blowing his load or just becoming aroused.
Some guys get a semi-boner to playfuly slap each other in the face with it.
by Tiea August 04, 2008
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When your erection is only semi, it does not go all the way. This is actually more embaressing than a true boner because people think you 'cannot get it up'
HAHHAHAHA LOOK PHIL HAS A SEMI BONER OVER CHARLOTTE!
ITS PROBABLY OVER JOHNNY CAUSE ONLY HOMOS GET SEMI BONERS!
by chloerose444 August 14, 2008
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Cleveland Steamer Plush

The vengeful act of crapping on a lover's chest while they sleep.

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4
when the tip of your cock is floppy but the rest is as hard as a brick.
omg tommy you have a semi boner.
by tommysucks February 19, 2017
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