What does the slang phrase mean....?

Question

When a woman says their "gettin it in"?

Answer 1

...They're having unprotected s*x

Answer 2

I'm from Liverpool - I havent heard that exact phrase but if sum1 were to say, ''I'll get a drink in.''

They would be buying a round of drinks.

Answer 3

Hah!  Only dirty-minded people see sexual allusion in ladies saying they're getting it in.  They could be referring to any staple household product which is currently being delivered!