To get balls deep in anything; whether it be a person, place, thing, or idea. In addition, any noun also has an ass. Therefore, it is possible to get into both. However, to accomplish this feat, one must use the possessive.
We didn't know where to go for food so Larry suggested we get up in some Taco Bell's ass.
That dude pissed me off so i got right up in that ass and tore it up!
I'm going to get up in her ass's ass.