I do the shirt thing a LOT. In my previous school, the girls were very bothered by my shamelessness/pride of my body, because I usually didn't put the towel around all of my body after showering after gym class. I mostly put it around my waist.
I also tend to lounge around the apartment when shirtless, and I have to actively resist the impulse of taking my shirt off in summer. Wearing undergarments on the upper body never felt natural to me, even the binder makes me feel girly and silly, though I love its effects.
Some years ago, I slept at a male friend's. I took off my shirt and slept in my underwear, and I didn't wear a bra. Turns out that what I percieved as completely normal was percieved as a sexual invite by my friend, so I had to wake up and find his hands all over my body. He was groping me while I slept. It wasn't the nicest of experiences.
I have to peek at what girls are doing in the locker room and then try to imitate their actions. This is just another part of my gender confusion: when I am with cis-girls, I worry about not passing for a girl, even though I biologically am one.
Yes, I am a very confused person, as you see.