The concept of sin is a complex one, influenced by personal beliefs and religious interpretations. There is no universal answer to whether kissing in bed is a sin.
Different religions and denominations have varying perspectives on intimacy and sexual behavior. Some may consider any sexual activity outside of marriage a sin, while others may have more lenient views.
It's important to consult religious texts and teachings or speak with a spiritual leader for guidance on specific beliefs and practices.
Ultimately, the question of whether kissing in bed is a sin is a personal one that should be addressed through individual reflection and spiritual exploration.