Hire someone to do it for you.

have You tried tmall.com already?

  An electric toilet seat, are you kidding? That's actually a thing, it doesn't sound safe. What if you sit on it and forget it's plugged in? That last moment of realization as you flush and see the spark, your life flashing before your eyes and you've not yet pulled your drawers up. I mean, what a way to go. Where's the dignity?

PS: Pigu? Is it just me or does that sound like a really nasty urinary infection?

hm... may I suggest You to better warm all bathroom, then only a seat?

I wouldn't like the situation that butt is comfy, but all of my body is shaking, or I have to sit on toilet with a naked butt, but in coat...

best thermal comfort... if You do not have central heating there - install air heater (kind of radiator with build in fan) that You can hang on the wall (in some place that You will have slightly chance to pour it in water...). that item warms up small room very quick, so electricity won't cost You fortune.

cost of that item should not exceed 200-300 RMB, while warmed toilet seat costs the same or more, but gives some comfort only to Your rear end...

get a cushioned seat, not as cold as a hard seat.

There is a kind of soft cushion to put on your toilet seat, you don't need to connect it with electrocity.