When I was growing up at my grandparents' house, when one of them would get my bath or shower ready for the night, it wasn't wholly uncommon for me to use the toilet for either number right before I got in, while they were still in the bathroom. That went until my early teens. That's never been the case in my regular home, though, everybody uses the bathroom solo and my mom would have me go before she got everything ready. Now I'm obviously old enough to do it myself, so it never happens anymore.
I never thought it was weird, but then again, I'm kinda weird.