What's a headwarmer?

[Fort Jefferson]

I was out shopping the other day when I overheard two lads talking, and one said,

"He gave her a headwarmer, and he'd only just met her"

Never heard this one before.

[A.Wang]

Shoved her head in his crotch for so long that she's nicely "warmed" up and nearly suffocated?

[y2blade]

farted on her face?

[karona]

A.Wang said:

Shoved her head in his crotch for so long that she's nicely "warmed" up and nearly suffocated?

Substitute 'his' for 'her' and you're pretty close to the mark