A fork of Rural Dictionary
To make ones 'juice flow' means to arouse ones sexual appetite, expetially males. The phrase is derived from the chemical process that takes place before a dick gets hard. Blood and Dopamine flows to the dick making it hard and giving pleasure respectively.
Seeing Stephanie in her lingerie made my juice flow
To have an ejaculation.
My neighbor certainly has his "creative juices flowing". Him and his wife are expecting their 4th child come (no pun intended) next spring.
Shampo and conditioner.
I use flow juice to keep my flow lookin nice.