If it's very high don't lay down but keep moving.

Depending how high, sometimes people have to go to ER and get IV medications to lower it. If sugars stay too high for too long people can go into Ketoacidosis and even coma. Ask your doctor or pharmacist for advice if need be

it depends on your treatment. if you take face acting insulin you can give yourself a shot or you can drink lots of water and not eat anything that'll cause a spike and wait. thats all I know to do

I just drink water. If at all possible I lay down. Otherwise I just drink water...

And walk. Exercise brings it down. If you eat, make it protein. If it's really high, seek help.