I don't identify as a transperson or woman... gay guy. Yet, i have some decided on buttons when it comes to my breasts?
Growing up, i was skinny to the point of emaciation. Add to that, i have a sunken chest, so not only was i flat, i was concave. The last few years i've been going to the gym every other day and now have some chest... which i like.
A few years ago, i had an ongoing online connection with a Top/dom Who wanted me to have breasts. His desire connected to something in me and it became a bonding place for us. He sent me a breast pump (we lived 1000 miles apart) and asked me to pump for 10 minutes a day so i'd get "little titties" (i ended up pumping longer). The effect was not permanent, but did give me some perky little breasts, especially right after pumping. Probably not dissimilar to those Guys Who pump Their cocks?
my Top confessed to me that had we been in closer proximity, He would have found a way to (secretly) get hormones into me so that i would not only develop breast, but would also produce milk. The whole idea was a deep turn on for me that i don't claim to understand. i'm total bottom and do not think of myself as having a "cock," though i have no desire to be rid of my penis. For me, it's wired more like a clit than a penis, but i don't have a need/desire to be a woman... more like i'm a guy with some female wiring, but still a guy.
It's not the breasts themselves that turn me on... i cannot see myself doing it for me. It's about the desire/lust it evokes in a Guy for me that ends up turning me on. i need the connection to evoke the desire/need in me. The desire is there, but is responsive.