on the porch swing
after midnight
silent
together
last night

I think this falls short of a true Tanka. I’ve tried several arrangements of the lines but keep coming back to this as the strongest. In most of my Tanka I try to make three sequential lines work alone as a haiku. In this case, I might prefer this as a haiku:

silent together
on the porch swing
last night

I don’t know. As of this moment, I’m happy with both.