http://www.everydayhealth.com/health...6pLid%3D121148
Yawning indicates sexual arousal. If you ever yawned during foreplay, you can now explain to your partner that it’s not their fault. Several recent studies have found that a yawn could mean not boredom, but sexual arousal. Robert Provine, PhD, a neuroscientist, professor of psychology, and yawning expert, explained to MSNBC that
yawning is associated with a change of bodily state, for example, from sleeping to waking or waking to sleeping. When you’re in the middle of foreplay, a yawn could mean another state shift: from not aroused to aroused. Provine even speculates that orgasm and yawning may share a neurobehavioral heritage.