A lockscreen couple is what you call two people that share the same lockscreen wallpaper on their smartphone. Usually annoying overly lovey-dovey couples make a picture together and put it as their lockscreen wallpaper to show everyone their love.
Dan: "Omg, ur lockscreen is amazing, I want it."
Lucy: "Here you go! <Sends picture>"
Dan: "Omg, we're a lockscreen couple now. That's bare dank."
Stranger 1: "Gasp! We have the same lockscreen wallpaper!"
Stranger 2: "Nooo! That means we're a Lockscreen Couple!"
By analogy with sunblock and sunscreen (assuming sunblock deflects the sun's rays and sunscreen absorbs them), a cockscreen does not block cock, she absorbs it. Thus, you are not completely blocked from the friend, but may have to sleep with the cockscreen first to get through.
"That girl Dana there is being a total cockblock for her hot friend Jennifer!"
"Nah, she's just a cockscreen. Give her some lovin' and you'll get through, trust me."
It is said of the situation where a person has the bad luck to make contact with his testicles against an undefined surface or object, intentioned or not.
Given the nature of the word, it is more appropriate to design cases where the interaction is made with a moving object, for example, a ball.
Although it is extremely painful for the victim, it tends to be considerably funny to people who witness it.
Today in the baseball game the pitcher took a nutshot; the baseball hit him in the nuts.
Man, I just watched the funniest nutshot video ever.