alright now you wanna learn summonings, we'll learn snake summonings
A powerful jutsu, Ninpo Kuchiyose allows a ninja to summon animals, objects and the dead to fight on their behalf. The ninja normally signs a blood contract with the animal species, which allows them to summon different size and skill levels of creature. The ability to summon more advanced animals largely depends upon the amount of chakra the ninja can muster to perform the jutsu. By signing this contract, the creatures themselves can also reverse summon the contract signer to their location.
The type of animal summoned is determined by the contract. The blood is used as a signature to make the contract, which can be written on a scroll or tattoo, valid. Once summoned, the animal can perform a task or help the user in battle.
Most summons (if not all) appear to have their own "king" or "boss" that rules over their own kind. For example: to the Toads there is Gamabunta, for the Snakes there is Manda, for the Slugs there is Katsuyu and for the monkeys there is Enma.
It would that seem that once someone has signed the summoning contract, the animal of the contract can also summon the human, as seen with Gamakichi summoning Naruto to the toad mountain.
Specially prepared scrolls are used for any weapon summons or a variety of articles, such as puppets. Kankuro, Tenten and Kotetsu Hagane use this version of the technique.
sign your name in blood
*a contract appears*