What did Heidi do?

Good morning. Here is cheeky Heidi, I call her HideyHi. 

Last night I had a quick visit to the bathroom, when Heidi did something which caused me to dissolve into fits of laughter, and I have been chuckling ever since. It all happened in a flash, I don't know who was more surprised, me or her. She seems to have overcome her health problems, but another blood test is on the cards in six weeks time, just to monitor her condition. In the meantime she is back to her energetic self and is darting around like any excited four year old would.

So, this is my question to you, get your thinking caps on. What did Heidi do last night, which I suspect she will never do again? Ha ha, it was so funny, pity I didn't have a camera rolling. It could have made me £250 if I had filmed it and sent it to, You have been Framed, but I am not in the habit of taking a camera to the toilet with me.

All ideas in the comments please, I will give a prize to the one who comes up with the right answer. If no one gets it, I'll give a prize to the funniest idea. The competition will close in 24 hours so you have until 10.00am tomorrow morning, UK time.

She is now parked right in front of the keyboard and I am typing with one hand. What a sweetheart she is.
Catch you soon. Toodle pip.