I agree with a lot already said on here.
On nice days, pack his diaper bag with the things you will need. Diapers, baby powder, baby wipes, bottle, bib, etc.
Go to places he may like. Kiddie movie at the movies, sand castles at beach, feed duckies at park, playground, sandbox, zoo, aquarium, amusement park, Botanical gardens, field to play with a ball.
Or indoors sitting on floor playing blocks, crayons 🖍 coloring books, arts crafts, board games, things like that.
Spoon feed him, bottle feed, breast feed, give baths, occasional spanking, just spend quality time treating him as you would any child in his diapers.