Declare the additional creature as an attacker, attacking an opponent unable to block it.
When the creature is unblocked, activate Medomai's ninjitsu ability by paying ({2} magic symbol) ({U} magic symbol) ({B} magic symbol) and returning the creature to your hand, putting Medomai onto the battlefield tapped and attacking.
Deal combat damage with Medomai, triggering its ability, causing you to take an extra turn after this one.
Before the combat phase ends, activate the creature card in your hand's ninjutsu ability by paying ({2} magic symbol) ({U} magic symbol) ({B} magic symbol) and returning Medomai from the battlefield to your hand, putting the creature onto the battlefield tapped and attacking.