lol, I got that wrong, I meant to say the eyes (right in Itachi's case, left in Sasuke's case) always bleed when using the Amaterasu technique. The moon eye hurts after using Tsukuyomi, the sun eye bleeds when using Amaterasu, and both go white when using Susanoo.
The time when Itachi poked Sasuke's forehead and the blood was shown dripping over Sasuke's left eye, that was a foreshadowing of the fact that Itachi transferred his Amaterasu. But Sasuke did awaken his own Mangekyou later on and used his own Amaterasu and Tsukuyomi. So here's my question, did Itachi only transfer the Amaterasu technique to Sasuke or all of his techniques. If it was Amaterasu only, does this mean that the spiritual weapons are lost if Sasuke uses Susanoo in the future, so we might get to really see what Susanoo can do on it's own.