I actually just went to the dentist and asked when the best time was to floss. She informed me that any time is fine as long as you floss! She even suggested getting the floss picks and flossing in the car. At work in the shower. Where ever you have a moment. Hope it helps.
Flossing is very important, try talking to you hygenist / dentist about it's importance. That will really help you to get the bigger picture and you will not be able to forget due to adverse consequences in long term. Try using waterpik from Costco/Amazon. It's the best flossing tool and my dentist recommended it.
I use floss picks instead of traditional floss. They come in a package, so I just leave the package where I'll see it, usually by the rest of my tooth brushing stuff. It also helps me remember if I've eaten recently, because then I can feel the food in my teeth and it makes me want to get it out.
I have flossing as step two in a three-step ritual. First I brush my teeth, then floss, then use mouthwash. I never do one without the other which is how I don’t forget.
I have my toothbrush, mouthwash & flossers all next to each other so when I brush, I floss & use the mouthwash all at the same time…
I go through my evening routine one by one ticking things off as I go. I find there is a direct correlation between not flossing and gum infections which helps me remember.