One might think that after spending six years serving as a Galaxy Garrison senior officer, leading dozens of dangerous missions into enemy territory, personally overseeing the deaths of Zarkon’s highest generals, and getting his arm blown off only to be replaced by a weaponized prosthetic against his will, Shiro would be prepared for anything the Universe threw at him. He was not prepared for Keith and Lance.

His arm wasn't the only thing the Galra changed. They also gave him certain... needs. Shiro learns to make it work for him.