Give him a copy of "Oedipus Rex."

You should probably get a child psychologist involved here, that can indicate a lot of problems you may not know about.

I don't recommend spanking him.

Rule 34! (There is a type of **** for every possible interest.) Yep, MILF & panties… While this is not necessarily an abnormal type of behavior (except for the number of panties used) it is a situation requiring care. At the very least it becomes a teaching situation about inappropriate use of someone else’s personal property. It amazed me that I actually had to tell my son not to toss his “used” tissues under his bed and leave them there stinking up his room. I actually had to suggest to him that he use a sock and then toss it in the dirty clothes hamper. As I explained “nobody expects a sock to smell good.” Son might be using the panties because they are soft and smooth - If that’s the case it’s not a serious issue except for the fact that they were yours and not his. Oh and then there is the possibility it somehow excites him to wear panties - Thats not necessarily an issue, but if that’s the case he needs his own. Finally he might be using them because they are YOUR panties - If that’s the case you have more potential for problems, especially if he’s been watching MILF ****. In truth, he’s at the age where he is at the least experimenting with achieving sexual self pleasure. Be glad he’s probably not impregnating anyone. He needs to understand the boundaries of what is acceptable and using Mom’s panties like this is not acceptable. Maybe he needs his own panties or softer socks and needs to understand that he should put them in the hamper after use.