J.W.
Both of my kids did this. I think its a stage of laziness or going back to being The baby. Both both stopped after a little whle. Try not scolding but put him on the potty more often and when he does go , tell him how big a boy he is; maybe a small reward; or how proud you are of him. Hope this helps... J. P.S. My grandchildren like for me to read them a short book while they were sitting there.