Metapsionic feats are to psionics as metamagic feats are to spells. Metapsionic feats allow a psionic character to enhance the manifestation of a regular power. Using a metapsionic feat doesn’t take any longer but does increase the total power point cost to manifest the power.
A psionic character can use multiple metapsionic feats on a power, and the extra power point cost is cumulative, but a power altered by metapsionic feats can never cost more power points than the manifester’s level minus one (minimum 1).
With the proper item creation feat, you can store a power enhanced by a metapsionic feat in an item, such as a psionic tattoo.