Your partner can touch you almost anywhere and you won't feel uncomfortable. A friend can touch your head, shoulders, hands, and upper back without ruffling your feathers. Your mother can touch you in the same places a friend can touch you, but she is also welcome to touch your lower back. Your uncle better not try to touch you anywhere but your arms and upper back, and a stranger can only touch your hands without causing you to be alarmed.
These are the results of a fascinating study by researchers from Aalto University in Finland, the University of Oxford, and the University of Turku in Finland. They developed "relationship-specific maps of bodily regions where social touch is allowed in a large cross-cultural dataset of over 1,368 people."