balls-deep

With the penis fully immersed in an orifice, more often the anus or vagina than the mouth.

I like to fuck balls-deep. If they can't take it all it's not worth the time.

Having the penis fully immersed in an orifice, more often the anus or vagina than the mouth.

He was balls-deep in his girlfriend and cumming in buckets.

Fully committed to a situation.

I'm balls-deep into this essay; no turning back.