Nipple coverings that are held in place by friction with the (erect) nipples themselves rather than adhesive or straps or piercings. If there isn't enough detail to tell, use pasties instead.

Since most coverings obscure vision, this generally means the they need to cover the nipples only and not cover the areolas or other parts of the breasts.

Also see:

• nipple_band
• nipple_shield
• pasties