The more you do, the more he will laze about. It isn't that he's letting you do it cause he's lazy. It's more he cannot detect the hand you are offering to get him to join in. All he detect is your hand letting go of his to go about your business. I saw a solution to this on a gaming board. The son was engrossed with war----t and the mother got him of it by taking his hand and leading him to another machine nearby to play another game together. What didn't work was her playing war----t with him. He stopped playing and resumed when she had to give up. 

Following the same logic if he's lazing on one settee and you take him by the hand to another nearby and you both laze on it, this could break the cycle. I'm not saying it will work. I presume you might have to keep hold of his hand which he might not want to do. If he returns to his original settee, stay where you are and see if he becomes uneasy with your presence. Even if it takes all night. If he does he will have to do something and it won't be lazing about. A suggestion.