A fork of Rural Dictionary
When a man sticks his finger up his ass-hole in order to tickle his prostate, causing an instant, extreme orgasm. The prostate (looking like a walnut) is commonly used as a sex toy for vietnamese people.
A walnut is someone who hasn't been cracked open to reality. Someone really innocent or naive.
"That bitch José is such a walnut! He doesn't even know what a lemon party is!"