". . .but that means I can't blather on...giggle. I'm feeling rather stupid now..."

Almeda, if you don't want to blather on, make yourself a "sign" or symbol to remind you to get back to the subject and share it with him? My T commented once that I was like a car on a highway and I'd take early exits and then clover leaf around after awhile and come back on :-) I'd get scared of what I was saying. But it was very helpful, that image; she could mention it and eventually I got so I could see it and stop myself before I exited (probably slowed down though :-)

What your T says is just supposed to help you hear yourself! So don't "switch the subject" by focusing on what he "thinks" instead of what you're doing/saying. Doesn't matter if he doesn't want to hear you blather on; only matters if you do or don't want to blather on :-)