I like petite women with small breasts. Though my gf does not match that, I am still very attracted to her, because we have so much in common. But, you asked. The attraction, for me, is not just physical. There has to be another component with her personality that is attractive also.
Besides, I had one gf who had big breasts. She had two black eyes after we were...very vigorous. Boy was her guy friend mad at me. Her breasts kept hitting her in the face! I didn't know they could do that! (No, I'm not joking. It was really bizarre.)
I have a long time interest in psychology, specializing in relationship dynamics for 30 years.
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