What do you mean by China hamburger?

Intimate behavior. "Couple's Chinese hamburger" is a kind of network language, which means that couples are too close in public, which is similar to an expression of "showing love". "Chinese hamburger" was originally a traditional food in Shaanxi, and the meat was sandwiched between two pieces of steamed bread. In network language, "meat" refers to one of the lovers, and "steamed bread" refers to the other, so "meat bun" refers to the other.