Does sex makes your breast bigger an body ?

Intermittently: Sex precedes enlargement of both breasts and the belly, but after the baby is born, the belly goes down close to its prior size (hard to get back to "never-pregnant" nulliparous size). After the baby is done breastfeeding, the breasts go down to near their prior size (also hard to get back to the prior pre-pregnant breast size and texture). So, if not planning to raise a family, use contraception.