A combination of heat and cold! Use one of those bug pens (or a cotton ball dipped into very hot - about 70°C - water) and press it against the bite for about 10-15 seconds. Repeat if necessary.
Afterwards, use ice, frozen peas, a cool pack, or a cloth saturated with a mixture of vinegar and cold water, and apply it to the bite.
There is a temperature range where the bite is de-itched, but you aren't burned. Good luck finding it. This technique either works really well or it works really well and you end up with a blister.