I line my belly band with baby diapers, a size 3 cut into 3 works great for my lil boys. Just change frequently.
Take him outside, without it (on a leash, so he know he has a job...and celebrate every "hyke") and when he is inside wearing the belly band, say "no" or "hey" when he hykes, so he knows there is a difference.
So glad he has you.
Good luck |