A euphemism (q.v.) for a tutor in a foreign language or languages who, as the term implies, give tuition in bed. A term more commonly used by men of women than vice versa. Those who practise hypnopaedic techniques use a different kind of dictionary.
*Found in The Penguin Dictionary of Litetary Terms and Literary Theory, by J.A. Cuddon.
Please, please, take notice of the last sentence. Is this a joke Mr. Cuddon? Did you really think you had to make this clear? I'm just giving you some credit by thinking you're fucking around with readers. Great Oxford humor, no doubt. Just made my day.