Exist with another being, and acknowledge that you have never before been and never again will you be.
Thank the causal lineage that created you, in prayer or dictation, with, to or for your companion.
Come up with a moment-name for yourself, a small poem celebrating the oneness of body and moment, so your causal descendants can thank you, in whatever way they feel the word.
Realize that one is gone, and notice you are anew.