gosh...party pooper, *clears throart*
Summoning technique is a unique kind of ninjutsu in which a ninja, by sacrificing a bit of blood and chakra, the user casts this space-time ninjutsu whcih brings a beast of the contract you summoned. It's to say, if I signed a contract with a pig and I made that jutsu, the pig would come.
It's important to notice that the chakra you sacrifice is proportional to the size of the animale you summon. The bigger, the more chakra.
The summonned animal can be later dismiss bby a variety of reasons, like getting seriously hurt, exhaustation and the summonner's will.
Summoning is not only for animals but too for ninja tools as seen in sasuke's uchiha's shuriken summoning tatoos, tenten's scroll or sasori's puppets.
*catches breath*
how was it?