Maybe this should be in the beginners forum, but because it is kinky...

I've never tried BD but am thinking of doing so.  I want to be responsible but also not unnecessarily inconvenient.  One question I have is when going from CBJ to CPIV and back.  It would seem to be inconvenient to put on a new cover. (And no, I am not including A2M or A2V.)  I realize one could go BBBJ to CPIV and back, but that is inconvenient as well.  That's why I am thinking of putting one cover on and just staying with that as I rotate her through the positions.

I will admit it, I'm a lazy bastard and I don't want to spend the next hour looking up all the anacronyms, and decoding your message! I do hope someone know what all that is, and can answer your question.

going from BJ to PIV is fine, even back again (if she doesn't mind it) is fine too, especially if you are using a good quality condom.

If she does BBBJ, suggest to her a female condom - that way there is no awkwardness, and you are both well-covered.  

K

It's a hygiene question about going from covered blow job to covered penis in vagina without swapping condoms.

It seems to me she'd just be getting her own saliva in her pussy so it should be okay.  But I'm not an immunologist.
 

The real problem with blowing someone covered and then switching to penetration isn't hygiene, it is the chance of putting small micro tears in the condom. Even if the giver is excellent and never bumps with teeth, the risk is pretty up there. Honestly, it is one of the reasons I prefer BBBJ.  
 

Anyway, I think you are over thinking this. I promise that putting a condom on or taking it off won't kill the mood