I disagree once again, the problem is that Elio could not ever define himself or conflate himself, and Oliver had known that was impossible from the start. their exchanging of identity through sex was a show of development for Elio in understanding the true nature of identity.

Maybe this: Love which exempts no one from loving in return, by dante, shows that love is a reflection of the self and an understanding of one's identity.

Basically, Echo is reinforcing the idea of interpersonal identification. Although in the dream Oliver says "you'll kill me if you stop", the phrase is actually said by Elio -- showing how they desire one another both to have each other but also to be one another. Through the exchanging and replacing of words. How do words and speech represent or shape identity?

He is giving himself to Elio much like he partook in enjoying himself via. the Apricot juice, because perhaps he sees himself in Elio, and thus can share himself with the other?