Force it down? I also notice it doesn't mix very well, but you just gotta chug it.
I would not recommend mixing it with a smoothie. I don't know if mixing it with foods can decrease its cleansing effects, so I wouldn't try it.
Throughout the day I would drink fruit/vegetables smoothies mixed with flaxseeds (for extra cleansing). Drink about 8 cups of water throughout the day as well. Then before I go to bed, drink the Bowel Cleanse with with 1-2 cups of water.
You'll be going to the bathroom (urinating from all the water) throughout the night, but it's worth it.