The female equivalent of a boner. Called an invisiboner for obvious reasons.
Megan Fox gives a lot of lesbians an invisiboner.
The term you use when you use the upper lining of your shorts/underwear/trousers to support your penis so as to conceal your early morning boner.
Used when you want to prevent awkward conversations with your parents/siblings or any other person around you when you wake up!
Jim: man how come you never get caught with a boner by your wife in the morning?
Tom: looks like you are unaware of the secrets of the invisiboner!