Nocturnal penile tumescence (NPT) is a spontaneous boner during sleep (usually REM) or when waking. Basically the technical term for 'morning wood'.
Involuntary spasmodic contractions of the hands and feet known as carpopedal spasms and are observed in hyperventilation, calcium deprivation, and
(or just before orgasm)
Leading up to orgasm and actual orgasm involves a ton of involuntary muscle contractions, carpopedal spasms are just one type that may occur. Next time you witness an orgasm have a look at the feet, you might see the big toe held straight, the other toes bent, and the foot arched, this is a typical carpopedal spasm.