Brown wings have an 'expiry time' of twelve months and are revoked after that period unless you keep up your 'air-time'. This constitutes at least one trip up bourneville boulevard from the initial date that you joined the Brown Squadron. Failure to do so will see you grounded,and no airman wishes that upon himself. Sticking your finger up her bum does not qualify you as a holder of brown wings, you will only be ranked as air cadet for this particular feat.

"I got my brown wings with Sarah the other night"

John is allways trying to redwing Jane but now he is trying to brown wing her being he only gets once a month to redwing

Dude, I just earnt my brown wings with my girlfriend last night, she was so shocked when I put it in her arse.

As in "have you earned your brownwings yet?"
"Have you given your bird one up the arse yet?"
"Yes I have earned my brownwings"

"I fucked that slut Jane last night, she wanted it up the arse"

"Congratulations mate, you know have your brown wings"

Brian earned his brown wings last night when he scarfed Jenna's chocolate starfish.