I won't fuck my wife's pregnant sister in the pussy, let her do the anus

I'm holding my wife's hand and I'm worried she's pregnant and she's got a dick in her anus

A hint of sex? Let's go to the anus, I'm pregnant, there's no room

My mother is already pregnant, but I'm still going to come in the anus, just in case

The doctor told me not to fuck before the birth. But he didn't mention ass