"Formula" in the context of a porn video tag refers to a specific sexual act or scenario involving two or more participants. This term may represent any of the following:
1. A sexual interaction that is calculated, planned, or carefully thought out.
2. A particular combination of sexual activities or positions that are being performed by the individuals involved.
3. The use of a specific technique or formula to achieve pleasure or orgasm for all participants.
4. A combination of sexual practices that have been predetermined and agreed upon beforehand, following an established pattern.
5. A scene where one or more partners are engaging in role play as scientists, mathematicians, or any other profession involving formulas or equations.
In all cases, the tag "Formula" implies a calculated and methodical approach to sexual activities within the context of adult entertainment.