Oxytocin
What it does: Secreted by the pituitary gland, oxytocin stimulates the prostate, causes muscle contractions and sensitizes nerves. Research has shown that increased oxytocin produces more intense orgasms.
How it makes you feel: Oxytocin is known as the "cuddling hormone" because it causes you to feel a connection and bond with your lover. It's also found in women's breast milk, helping to create a bond between baby and mother.
If you enjoy cuddling with your girl after sex, chances are you know the effects of oxytocin well.