It might be a dumb question but I don’t want to risk fucking him up somehow—what I’m most worried about is his stuffing getting mildew-y or otherwise borked. I’m pretty sure, almost certain actually, he’s polyester inside. Do I just dunk him in some soapy water, scrub him, and leave him in the sun for a while? Can I throw him in the washer next time I do laundry? He’d fucking love that.
What the other comment said is good, just want to add:
Use a lower spin speed if you're going to use a washing machine and use a tight-fitting delicates bag or tie a knot in a delicates bag if it's too big - not tight enough that it's going to squeeze any air out of your toy but tight enough like you're packing it into a bag. This will help ensure that the stuffing doesn't get shifted around too much.
If it's small you might use a sock instead of a delicates bag. You could also use stockings, an old t-shirt, or a pillowcase.
The other thing I'd recommend doing, especially if it's larger, is after the wash placing it between a dry towel or something similar and giving it a reasonable press on all parts of it to get the excess moisture out before air drying. Don't wring it but a firm press on a flatter surface between a towel or two will get a lot of moisture out and it will ensure that the toy dries properly without getting mildew-y