Even methane (natural gas) is lighter than air, but not by much. Carbon dioxide, which is contained in the air we breathe out and is also easily and safely manufactured by mixing bicarbonate of soda and vinegar, is heavier than air. It tends to sink to the floor and accumulate. So it's a good job that houses aren't air tight.
Cuddling, holding, and sexual play releases chemicals, like oxytocin, in the brain that create a sense of well-being and happiness, says Dr. Renee Horowitz, an ob-gyn who recently opened the Center for Sexual Wellness in Farmington Hills, Michigan.
Oxytocin is naturally produced in the hypothalamus and released from the pituitary gland during hugging, touching, and orgasm. In fact, human blood concentrations of oxytocin have been reported to be higher amongst people who claim to be falling in love.