The Stream

[syntheticsunset]

I see two tiny typos: I think you meant "its pliable hands" and "tree trunk's shade".

Interesting that you use so many possessives (willow's, water's, summer's, trunk's, blades of the bank, curve of your calf, etc.). I think that's rather fitting in a poem about voyeurism.

The action is a bit slow, and I wish the surprise at the ending were stronger, but there are several bits I like a lot.

The Stream

Behind the willow's curtain, I'm glad you dropped the word "tree". This is much tighter.
tremulously i watched
as all voyeurs must,
wanting to be caught. Love this!

You stood at water’s edge,
seduced by summer's wind
it's pliable hands pressing.
Your outline thrilled me,
and I held you through light-dappled leaves. I like "held" much better than "hugged" here.

A twirl, a swirl;
you danced on the blades of the bank,
mirroring eddies in the water. Nice image

With arms outstretched
to catch the cooling sun. This is a sentence fragment. Perhaps a comma would work better than a period?
You stepped through the silvered surface
till it lapped the curve of your calf.

I returned behind tree trunks shade, "I returned behind" feels a little pedestrian.
no screaming thought had room to breathe. Nice sensation of struggling to hold one's breath despite a racing heart!
Closer, ever closer,
then splash, and splash again.
You sat within the willow's reach
and splashing, called my name. This is unexpected, but I feel like it's also a bit of a let down. Perhaps I'm reading it wrong, but the scene feels lighthearted, as if she knew you were there the whole time, and the stakes of being caught were never very high.