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The state of the Penis which is not quite a Semi, but definitely not completely flaccid.

'Third on' - Literately a third of the way through the erection stage.

"Dude, she's almost hot, I've kinda got a third on going on!"

"Wow that was an long drive, I've got a third on 'cause of the chaffage.
by funkymunkey101 March 15, 2009
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2
An erection that is between a Semi and a full on raging boner
Hey man, did you see those homeless men jerking each other off? It gave me a third on
by bobskaggs June 07, 2017
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