Not sure you can do this comfortably, but here's what I noted using Progynova:
Lumps.
Pretty much as described - and I had man-boobs first, I was always "chesty."
Now, how can you check?
Can you press (GENTLY) on your breasts? If everything is jiggly and sloppy, it's just fatty tissue.
If it's got the feeling of ... Well, ever unravel a plant? (Rope works, too.) You'll feel glandular tissue, which will be simlar in a way to that rope or fibrous plant. the fat goes around the glands and ducts. If it hurts? Yeah, you have boobs. ;-)
because I'm not taking estrogens of any kind at this point, I can feel the ductwork with minimal discomfort. It's like that rope, or tree roots, or fibrous plant stripped apart. then there's a different consistency, all jiggy, over the top; that's fat. At the same time, there are pectoral muscles; they're deeper, under the breasts, and support the breast tissue - you may want to build them a little, using a decline bench press, which will focus on the bottom of the Pecs - but you need to be careful, you don't want too muscular a chest - build soem volume (10-rep range, bodybuilder style), and you'll need to research the narroe or wide grip to see which will help point boobs in the right direction.
Mine don't sag because I have good, solid pecs... But I don't look girlie, either - so do LOTS of research first. ;-)
And if you don't care about any sag? DON'T lift. Why risk growing in the wrong directions?