Hum, once your nipples hurt from ongoing HRT stimulated breast growth, it's not something that seems of any priority, to say but the least.
I do have a breast pump, have tried, got some 'pre-stuff' (only on one side) but that is more then a year ago.
It is VERY much different if one seriously intends to actually want to feed a baby in the family. No question for me, and not weird at all.
However, leaking into your bra just for the heck of it... it REALLY can get messy, and can get on your nerves too.
It's all a bit like the "would you like to have periods" thread. If I was the age and could help to feed a baby, I was in the front-line.
Just to 'pump-up' one's breasts... as I said, I tried and for now I think it was 'educational' of sorts and that's that

Axélle