Deadpool is pretty good resource on this, though he would usually be in both a bad-ass environment but still make it slap stick comedy. It really depends on the series / camo
There's always the make it very mater-o-fact-I'm-used-to-this-and-don't-even-notice method.
Character: Where is your arm?
Character 2: It's right-- oh... huh... I don't know... somewhere back were we were I guess... I guess that explains the weird tingling. Whatever it'll be back soon.
You can also have the character be horribly accident prone, and since limbs regenerate the body doesn't have to work as hard to keep itself together.
Then there's always the 'comfortable enough with leaving limbs everywhere that I do it to prank other people or make my own Halloween decorations"
Also just don't add the graphic blood and just focus on the concept, and it gets much easier to translate into a joke or lighthearted moment.
For my comic I have a character that sorta does that, cuts himself in pieces (and puts himself back together) with each piece regenerating into a copy of him- (old art, I'm sorry for the quality)