A handjob from a girl who is on her period and used the mentrual fluid as a lubricant.
"Did you have sex with her?" "No, she was on her period so she gave me a crimson handshake."
When a girl who is menstruating uses her period blood as lubricant for a hand job.
She didn't have any Astro-glide, so I had to ask her for a Crimson Handshake.