My belly button smells like cheese?

Wash better: Usually an indicator of inadequate hygiene--use soap & water--cotton tip if cannot get rag & finger in to clean deeply. Be gentle, sometimes base will bleed a little w/friction.

Better hygiene: If the smell disturbs you, the only real recommendation would be as with a bad smell from anywhere else on the skin; better hygiene.

Did u eat burger or: Pizza last night b4 u went to bed?(just kidding!) not sure but could just be accumulation of scaly debris, greasy materials etc. Or perhaps a sign of diabetes. Get checked up by your md. Try cleaning the area with cotton buds soaked with peroxide. While u are taking a shower, u can clean the area with soap and water. Go see your dr as needed.Take care!