Sensual breast massage is most often part of lovemaking - when a woman is highly aroused the breasts become more sensitive and breast touch feels even better.
Before trying to include sensual breast massage in your lovemaking, make sure she is fully aroused - use
fingering, sex, or other kinds of erotic stimulation to get her fully aroused and ready to receive breast massage.
Above all, communicate and pay attention. Pay exquisite attention to your lover during lovemaking and notice - does more pressure on her nipples make her gasp with pleasure? Or would she prefer a light stroke? Paying attention to your lover is the sexiest skill you can bring to lovemaking!