Is it normal to kiss your parents on the lips?
Depends.It depends
It can be normal in some families and cultures, while others stick to cheek or forehead kisses. What matters is that everyone involved feels comfortable and can say no without pressure.
Families show affection in all kinds of ways. A quick kiss on the lips may feel completely ordinary in one household and unusual in another; there isn’t one universal rule for what counts as normal.
The useful test is comfort, not appearances. If you or your parent would rather have a hug, cheek kiss, or no kiss, that boundary is fine—and affection shouldn’t be something anyone has to accept to keep the peace.