Defined as: a state of being deprived of sexual stimulus with other people (one hopes the sufferer restricts themselves to humans) either due to self-imposed abstinence or unfavourable circumstances that so frustrates an individual that their behaviour becomes irrational and irate.
Addendum: may manifest itself in instances of violent outbursts against inanimate objects or other individuals, often accompanied by a string of obscenities and profanities, usually ending in a scream of 'I NEED TO GET LAID!'.
Sometimes experienced by women as a symptom of pre-menstrual stress, often experienced by men when going without for any length of time.
Male friend (has a crush of epic proportions on female friend): <bites lip until it bleeds, says nothing and suffers in his own private hell>