Stimulate it.
It depends on the temperature you feel; if your going from hot to cold or cold to hot whether its with water or air/wind it could make your boobs hard. Also if you rub your nipple it could make them hard.
Yes, after extended use, nipple suction does make the enlargement and elongation permanent: the nipple will not stay erect, but will stay out and function like a normal nipple--enlarging when stimulated.
To make a simple fake nipple piercing, you need to obtain a nipple ring and bend the ring with pliers so that the ring looks like a U shape which you can then apply to your nipple and adjust to your own needs.
pointy stones
The timula
you have to give a little push, kinda like your flicking it. But not too much otherwise it won't catch air. Make sure to gently release after flicking.
To make your fingers vibrate, you can rapidly tap them on a hard surface, such as a desk or table, while keeping them relaxed. The rapid tapping motion creates a vibrating sensation in your fingers. You can also try flicking your fingers with a quick, forceful motion to make them vibrate.
Nipple stimulation also stimulates the production of oxytocin, which can lead to dilation.
Make a flicking gesture towards the top of the screen with your finger.
Use a pen, but take the ink out! Use cheap pen caps. Or use curled paper or other hard pointy/small objects:)
yes, you are isolating blood vessels and popping them.