It's about control. Something about them fighting off the male attention they get for having large br3sts is arousing to you, because it is a display of their "weakness".
It's pretty obvious- no psychology book needed.
You are implying that you are aroused by a woman who is self-conscious about her br3sts. You like having the dominant position. She is showing a weakness and you get turned on by it. It's about control.
I dated this girl who was sensitive about her breasts. She would even keep a shirt on during sex and didn't mind walking around bottomless in front of me, but wouldn't take her top off even during sex. I didn't find that all that sexy. She never liked me touching her breasts or talking about them. That was her only sexual hang-up. She could be walking around the house with no bottoms on and I would openly stare, but she didn't want me to look at or talk about her breasts.
Yeah, I even tried talking to her about it and told her I'm sure she has nice breasts and that I just love ******* no matter what size or shape, but that didn't help one bit.
Yeah, she seemed to have that issue where much of the attention she got from men was because of her breasts, which was really bad for me, considering that I really like breasts.
Not to me... :o