An item we couldn't miss here: Nipple suction cups. Lick them, squeeze them, put them on your nipples and they will suck them in! You can wear these for a longer time and it will enlarge your tits a little.

MEO recommends: For the best results, use EZ2FUCK-Lube (8226). Whilst a water based lubrication will work, it is not as effective. The cups can be tweeked and pulled, and the vacuum will encourage the nipples to swell!!