I'm not really a fan of it. I've done it a few times, and it just felt awkward to me every time. I dont feel I can give him a good proper blowjob when we're doing it. If I'm on top, then I cant really use my hands all the well, if he's on top I'm way more focused on choking hazards than pleasure. Being on our sides didn't feel all that right either.
Plus I like looking up at him seeing his face, instead all I see are his balls. Dont get me wrong I like them, like looking at them, holding them, and sucking on them, but it just seems odd seeing them upside down.
As for the recieving part, it still feels great, but it feels like it's missing something like he can't get a decent angle to really get in there.
It can be fun to do it, just to change things up a bit, but it isn't something I'd want to do all the time. Now it I'm giving him a BJ, and he can reach and give me so fingers. I'll take that every day please.