Tongue kissing (also for some reason called "French kissing" or "Frenching") is kissing another person whose mouth is open with your own open mouth, so you and your partner can feel the insides of each other's mouths with your tongues. For most people, the mouth is an "erogenous zone" -- which means when it is stimulated, you get sexually aroused. Tongue kissing -- exploring your partner's mouth with your tongue -- is one way to do this.
it means that when you kiss someone ur tonges touch
they also call it french kissing
It is an expression of deep love or foreplay to intercourse sex.
French kissing