The key to stopping this behavior is to figure out what you are getting out of it.
Are you really hungry? Sometimes after dinner I am still hungry. Thats when I turn to zero points + foods like fruits and veggies. A big bowl of broccoli (steamed or raw with yogurt ranch dip) help fill me up after dinner if I am not quite full. I also love cauliflower the same way. Another favorite (but not point free) is popcorn. I am one of those weird people that like plain white butter free popcorn. It is my favorite. It is only 2 pts for 3 cups (or 3 pts for 5 cups, if I am really feeling it). It is definitely a good option that wont kill my day.
Are you bored? Lets be honest, watching tv can be kinda boring. You are sitting still, staring at the tv, and it feels a little mindless. Luckily there are ways to keep you entertained without putting food into your mouth. You could learn to crochet or knit, and do these things while watching tv. You can also get on the computer and blog (obviously my drug of choice). Another great thing is to stand up and exercise while watching. Grab some hand weights, sit on a ball, stretch on the floor. Do anything to distract yourself from the food in the kitchen.
Are you craving? I'm not sure about all of you, but I have a sweet tooth, especially at night. I just want something sweet to curb my craving before I feel satisfied. I think I have figured out the root of this craving. After eating dinner, you have all the dinner tastes left in your mouth (and it might not taste very good anymore) and you want something that does taste good to replace it. My tip- brush your teeth. Brush your teeth right after dinner so you don't get that taste, and the taste of toothpaste is actually sweet, so that might help. I also try to drink water because that cool crisp clean taste helps with the craving too.
So there you have it. When you are sitting on the couch, thinking about grabbing a snack, sit and think "Am I hungry? Am I bored? Do I need to brush my teeth?" before grabbing that snack :)