You need a bath towel.....

Bring the water to the boil, stir in the oats, bring back to the boil, remove from heat, slap the lid on it, wrap in the towel to keep the heat in for as long as possible. Go to bed.

In the morning you should have cooked oats to portion out. I haven't tried this since last winter, so am writing from memory. If it doesn't work, ummm, Tulip offered the Cheerio alternative