1) Euphemism for a penis, where "one-eyed" refers to the external urethral orifice (or pee-hole) located at the tip of the penis' head.
2) One-eyed willy, both alternate spelling and definition.
Expression's origins: derived from the name popular character from the film "Goonies" (although this context has been permutated with time). See also dong, dick, schlong, willy, wang, johnson, cock.

When some little bitchboy is acting like a little tiny pee pee poo poo baby and messing up the group plans.