Nope, that wouldn't occur to me, especially since it's the guy talking about taking the girl to the B-part.
The mentioned reference to music, to me, is vague at best. Especially when compared to the sexual one.
To me, the "microphone" she's on (doing her best, showing him what she's got, trying to give him what he like; soft or hard) is one of flesh. Thus, the A part is foreplay, and he'd like to give her the B part (outlined by others before me), but they're not quite there yet. First she has to impress him with her skills; show him what she's got.
The "Yes, Boss" reference suggest the nature of their relationship is either D/s or M/s (Dominant and submissive or Master and slave, both of which are explained by your favorite BDSM dictionary). This also explains why she has to beg him permission to move on to the B part. First she must earn the privilege. Deserve it. Show him what she's got.
B part could actually also refer to Bondage, when I think of it.
The official music video is quite explaining, although the second last (4th) verse is missing. The complete song goes a little something like this:
They are on a date, and he's glad she could make it. He thinks they should get straight to business; thus, starting with foreplay. She wants to move on and do the next part (B), but first got to show him what she's got.
So close, and yet so far. He'd love to take her the B part, but they're not quite there yet. Grab that "mike" again and give it your best shot.
Oh yeah, that's what he calls sweat music. She's "playing" on his body. He really likes what she's doing, but she still has to work a little harder. Just a little harder.
Oh yeah! Way to go! Now we're really getting somewhere. It's getting hot in there. He wants her to do what she's doing one more time, before moving on to the next part.
Oh la la! I think you got me there, baby. Come along, here comes the B part.
No more foreplay, as 007 would express it.