New tricks or playtime?

So recently I have discovered that Sof rears on command - problem is I now can't work out how to switch it off or how many more tricks she has up her sleeve.

Today I was leading her back to her field and encouraged her to walk on (she was doing her usual amble) next thing I know she is on top of me with my coat in her mouth! Not what I was asking!

I'm not too worried about it, because she stops as soon as you tell her to - but I am a bit confused as to why now she is suddenly showing me her tricks now after a year and a half together. Is the jacket holding another taught trick or is she trying to play with me? Have I finally moved from owner to friend in Sofies world? If so do I need to re-establish myself as boss in this new relationship? Or am I just over-thinking things?

I am also not sure how to get her to stop performing as I am still not sure what it is I am doing that sets her off.

Most odd. She does like to keep me on my toes!