Firm, tight breasts with north-facing nipples.
Susan leant over and one of her perkies just popped out of her low-cut top.
An exercise program most notably done by Opal Crankshaft. Done in a mirror in order to maintain the 'perky' expression on Opal's face.
Opal: Hey Martha, your face is sagging. You've got to do some perkies!
Martha: What the heck are perkies? I've never heard of that in all my 70 years.
Amos: Ten hut! A little facial PT, huh?
Opal: Yeah, you should try this. You're gonna love it! I do it all the time.
Amos: Might as well. If it's gonna make Martha look good it might make me look good too!