Is his litter box easy to jump into and “enticing”? I suspect that this is mostly because he isn’t neutered yet, but you can encourage him to use his box my making it “appealing”. Carefresh litter is really popular for litter training because it’s soft. Adding a nice fluffy hay layer on top and only providing hay in the litter boxes also helps (many of my buns will pee/poop anywhere they are eating hay). Making sure the box has low enough sides to encourage him to jump in easily is also helpful.
Some buns become associated with a particular spot, others will go where every the box is… and most are probably a little of both. So if you notice he always pees in a particular spot, adding a box there will help.
I would add another box in the room he gets to free roam in, and for now you might just want to put down some pee pads in other areas to help with your sanity before he’s neutered.
Ushering him to the box after the fact probably won’t help. One thing you can try is to lead him to his box routinely during play time and reward him with a small treat (such as a pellet) if he uses it.. but honestly I would probably just try to get him neutered as soon as he’s old enough (4 months or as soon as his testicles descend).
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The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.