;D hi...
I have posted this before but since you ask and no one has replied here goes.
Most guys... even the ones that hide it well, can be considered perv's (mmm hmmm me included)
But if your worried about the reaction, break it to them this way.
Honey, ever since I was a little girl I've been a bit insecure about my breast size. To that end I want to try to enhance them a bit, and I've found a nonsurgical way that seems to work for other girls. Fill in the noogleberry vacuum therapy bit here. If there is any opposition, add in there is no negative side, its inexpensive, and fun.
Then let him see some of the pics from the site of girls in domes, let him visualize that image of you doing whatever around the house pumped up. If this seems to cause any sort of interest go to the next step.
... put on the domes pump them a bit and show them off. If, ... this is a typical loving male, who loves breasts.....(yours) seeing them in such a fashion will most likely turn him on.
;D
take the rest from there. if you include him in the operation, let him pump you up say...I know most of my friends would be all for it at least privately.