hallcest
n.— «When asked if living together has brought sexual tension into their friendship, Mr. Danzig said “no” flatly, and Dewar said the same, emphatically. Neither report any awkward or indelicate moments, but when both genders use the same bathroom on the floor not much remains secret. Dating neighbors—known as “hallcest” or “dormcest”—is courting disaster given such close quarters, says Danzig.» —“In dorms, men and women now room together” by Melanie Stetson Freeman Christian Science Monitor (Boston, Massachusetts) Dec. 28, 2006. (source: Double-Tongued Dictionary)