One can prepare for fire and ice by filling two cups with liquid, one hot and one cold. To prevent injury, the warmed liquid should not be scorching hot, but it should be warmer than room temperature.
Any type of liquid is suitable, including water, juice, black tea, or flavored tea. Mint tea is a popular choice as the tingling sensation helps sustain erections.
The person performing oral sex should take liquid from one cup into their mouth. The liquid should be held at the back of the mouth, underneath the tongue. Then, as oral sex is performed, liquid covers the penis, enhancing the sensation. The liquid can then be swallowed or spat out before the process is repeated with the other liquid. The giver then alternates between hot and cold liquid as they perform fellatio.
Alternative techniques involve putting ice cubes in one's mouth, or incorporating oral sex with a hand job using heated massage oils.
As with all fellatio techniques, condoms should be used unless you know and are comfortable with your partner’s STI status.
A variation of fire and ice can also be performed on a woman. However, as female genitals are more sensitive, it’s best to avoid liquids that could cause numbness, such as mint tea.