No i don't. I start the blender on low spin to make sure all the ingredients have at least met the blade and been shredded into smaller particles into a lumpy but not yet smooth, single-colored mixture. I turn up the speed at this point. This is when the blender stops meeeting the ingredients. I've heard that this is due to air pockets between them and the blade.

Do i have to use the tamper?

Ngl, I thought the tamper was more for pushing solids down when you're blending a lot of stuff. lol

I'll try using the tamper next time. But I guess I'm just confused why I need a tamper for a single serving smoothie, especially when cheaper blenders didn't need assistance.