I place a couple of pork loins on the top shelf of the smoker and that basts them while they cook. Nothing like pork fat for basting.

I understand about mayo going bad...outside. But in an oven, smoker or grill? I don't baste the bird till after the skin starts to darken...just a little. I believe it helps keep the bird moist.

I'd like to do the pork on the top shelf but I got a char-grill bbq with a side smoker....no "verticle" room. I put a small pile of charcoal to one side of the grill with (wet mesquite, hickory or cherry wood) chunks on top. For extra smoke early on, I duplicate the same in the side smoker. After a few hours when the temp has reached 150* or so I just keep the main going..charcoal and wood chunks.