My big guy poops occasionally next to the box

I have a very large male Manx cat that I rescued several years ago. He was a wild stray and we got him neutered and all healthy. He's a big boy with big paws but he is still a little overweight. Anyhow, he have two other cats, both much smaller than Howie. I have four litter boxes that I clean daily. He sometimes poops in the box and he sometimes poops right next to it. I'll be in one room cleaning and he'll start hunching over to go so I pick him up and put him in the box where he finishes and covers it up. The vet has not found anything wrong with him and it's not like it's all the time or when the box is dirty. It's almost like he's lazy. He is sort of lazy by cat standards by the way. Luckily it's on concrete so not that big of a deal. Is there anything else I should try or should I just live with it. His power cuddles are worth the cleanup and he's awesome with my kids.

Hi @Mlord and welcome to TCS!

 I love your description of your boy..

I honestly don't know what else to suggest.. it really does just sound like sometimes he can't be bothered!  I'm assuming he doesn't have any trouble getting in and out of the boxes?

We do have this guide that just may help:

 [article="32366"]How To Solve Litterbox Problems In Cats The Ultimate Guide​[/article]