A plutino is a Pluto-like object, insofar as it has the same relative orbit as Pluto. These orbits are stabilized by an orbital resonance with Neptune, similar to Pluto's 3:2 orbital resonance. Plutinos form the inner part of the Kuiper belt.
... sperm.
The external urethral sphincter is the skeletal muscle that allows voluntary control over urination.
In the human female, the urethra is about 1-1.5 inches ...