The phrase "gotten it on" is an informal and slang expression for engaging in sexual activity. There are several other synonyms that can be used to describe the same thing, such as "hooking up," "doing the deed," "getting busy," "making love," "having sex," "getting freaky," "getting it on," "getting intimate," "getting down," and "getting lucky." Each of these expressions carries its own connotations and levels of crassness, so it's essential to choose the right word for the occasion. Whatever the term, the key is ensuring both parties are consenting and happy.