if you are asking this question in the context of human interaction, it depends on the situation and the consent of both individuals involved. Consent is essential in any physical interaction, and it is crucial to respect personal boundaries and comfort levels. If someone is wearing a diaper and wishes to sit on another person, they should ask for permission beforehand, and the other person has the right to decline if they are not comfortable with the request.
Remember, consent is a fundamental aspect of any respectful and appropriate interaction between individuals. Always communicate openly and ensure that everyone involved is comfortable and willing to participate in any physical contact.