Tongue pulls back slightly from the D position, blending into R. Sounds close to 'jr'.

Americans pronounce dresses as DREH-suhz (/ˈdrɛsəz/). In "dresses", the "dr" cluster blends into a "jr" sound — a natural American English pronunciation. This is called the DR Sounds Like JR, a hallmark of natural-sounding American speech. It comes out as DREH·suhz. Stress falls on the first syllable — keep everything else short and quick. You'll hear it in sentences like "She always dresses in a professional style".
Record yourself saying "dresses" and play it back. The mic stays on your device — nothing's uploaded.
2 syllables, 6 sounds. Tap a syllable to jump to its row, then explore each sound's mouth shape and how it's made.
Tongue pulls back slightly from the D position, blending into R. Sounds close to 'jr'.

Curl or bunch your tongue without letting the tip touch the roof of your mouth. Brace the sides of your tongue against your upper back teeth, and round your lips slightly.
Drop your jaw moderately. Touch the tongue tip behind the bottom front teeth and lift the mid-front part slightly toward the roof.

The textbook way isn't wrong — it's just not how anyone actually says it.
In "dresses", the "dr" cluster blends into a "jr" sound — a natural American English pronunciation. /d/ shifts toward /dʒ/ ("j"), so DR sounds like "jr".
Stress falls on the first syllable, not the others. Stretch DREH — keep everything else short and quick.
Don't pronounce the first syllable too fully. The unstressed syllable reduces to a schwa — the lazy "uh" sound — in casual speech.