For anyone who doesn't have a mother or older sister teaching them how to put on a bra that hooks behind: Start it upside down and backwards so the hook is in the front, the interior of the cups face outward, and the straps hang down. Hook it. Turn it around and flip it up. (then adjust to make sure you're actually in the cups and not getting pinched weirdly).
To remove, unhook behind, pull strap on one arm through coresponding arm sleeve and unhoop that arm, pull entire bra from other arm sleeve, all without removing your shirt.
.
I may be lazy.
@pommegrrl ty i was gonna comment the same thing
also, bras don't stop boobs from sagging, in fact they might even encourage it since the supporting muscles deteriorate