UST

From UnknowableWiki

UST (Unresolved Sexual Tension) is a term often used to designate the tense relationship between two characters in canon or fanon believed to be originated from repressed mutual attraction. It can deteriorate the two characters' interaction into a terse, often explosive one; UST often ends with a cathartic NC-17 scene, or a similarly effective narrative device.

UST can present itself intentionally (e.g. in a love/hate Lily/James fic) or unintentionally (e.g. Harry's obsession with Draco Malfoy's evilness in Harry Potter and the Half-Blood Prince was squeed over by many a H/D fangirl). The latter possibility is extremely frequent in the series: the most innocent of statements can be interpreted in a thousand shippy ways.

UST is sometimes used to a detrimental end; many authors see UST as a staple of the Lily/James relationship, subsequently using it conspicuously and succeeding in cutting out subtle relationship-building. Therefore, it is important to be wary of having so much UST that the resulting relationship is a shallow, physical one, but it is also important to be realistic about real-life relationships and the practicality of UST. Remember, too, that most readers want timely and plausible resolutions--so don't drag the UST on too much.