"Jerk" comes from the phrase "Jerking Off" which also means masturbating
"able" means having the ability to do something/opportunity do something Combine them together and you have "Jerkable"
In simpler words, Jerkable means being able to jerk off to something.
Joon Sung Kim: "Bro I jerked off to Hentai yesterday, that shit was awesome"
Aiden Lee: "Hentai??!! wtf man! that shit is unjerkable, how do you jerk off to animated characters"
OR
Aiden Lee: "bro did u see that Ash Kaashh gawk gawk video?"
Joshua Hwang: "Yeah man, that shit is jerkable as FUCK"
And dying in yo' bed many years from now, would ya be willing ta trade all da days from dis here day ta dat fo' one chance, just one chance, ta come back here as young men an' tell our enemies dat dey may take our lives but dey will never take our freedom ... YUB NUB!