Need a strategy for expressing with an oversupply problem please

[TinyDiamond]

I have had a few threads over the last few weeks and have had cracking advice from so many people regarding our very many bf issues.
I have now pretty much managed to get supply slightly more under control, still loads of milk and fast let down but dd seems to be coping slightly better most of the time.
Now, I completely stopped expressing to try and and calm things down but we are now at the point where I simply have to be able to leave her for some commitments and need to get something put in the freezer.
The last thing I want to do is exacerbate the oversupply problem again so I need to know the best way of going about this.
I block feed, used to be 5 hours but cut it down to 2-3 hours now per side.
The oversupply is much more of an issue on the left so should I avoid pumping on this side?
Is pumping one breast whilst she feeds on the other a no no? I'm guessing yes.
Arrrgh, please help

I had a bit of an oversupply problem. To express, I used to just feed from one side in the night, then express from the other side in the morning.

I don't know if this was the right thing to do, but for me it didn't exacerbate over production.

Good to know academy thanks. Did you keep your pump by your bed and do it straight away or have to properly get up to do it? Trying to figure out the easiest way

Goodness, I can't remember now! Possibly downstairs as an upright chair was more comfortable.