Being sexually aroused, excited by either watching or being walked on/over by several people.
Can be the sexual pleasure of inflicting pain, which makes this sub category of the sadomasochistic fetish. It involves trampling over another person, or of multiple people walking over another, or can be where the person has the desire to be the recipient of such behavior.
Can be simply the walking over a person, or of being walked on by another or by several persons. Infliction of pain is usually associated with this act, and is part of the BDSM culture, more notably the sadomasochistic sub culture.
Noteworthy: Similar to the 'crush fetish' however, the difference is that a person is the one underfoot, not an insect or object. As well, this generally does involve pain infliction, adding to its distinction from the 'crush fetish'.