The definition of dormcest is not set in stone. While some people consider it simply to mean any relationship between residents in a residence hall, others define it more strictly, as a sexual encounter between two persons of the same dorm. This activity is more or less a freshman behavior, since most upperclassmen live off campus and outside the residence halls. There are instances where an older student may be involved; like a suave RA or in the transfer student housing.
Most relationships in the dorms are often "hook ups", with students seeking some level of companionship, while remaining relatively free. The closeness and familiarity of many residents in a dorm, especially smaller unit buildings, give people chances to meet others they might otherwise not have had.