DO YOU WANT HIM TO THROW UP ON YOU IN DISGUST, CAIN?
Proceeds to attempt to yank his wrist free so that he can shake his hand around uselessly and get that human blood off him immediately! It looks just like Karkat's mutant, candy red which is so low in the hemospectrum that it's not even on it and it's touching his precious skin where his high purple blood flows throughout his own veins...] Bluh! Did you really have to smear it on my hand like that?
[Of course, he would never wipe it off on his precious, now clean clothes. Which is why he lurches towards Cain and gives him his own blood back, enjoy that.
Also, notice that Eridan still isn't over it. Whelp.]