The type of sex that necessitates a blood test afterwards when the STD status of the other person is unknown--intercourse (vaginal and anal), oral sex, ...anything that allows fluids to mingle.
"Did you fuck that girl last night?"
"Just a handjob, no blood test sex."
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.