I’ve had some suggestions:

If your young friend is into computers then he can store it in old pc case – you can fit a lot in them – no locks mum never looks

A small fire proof safe – locked and you can say photos and documents are stored plus toys

Hi Andrew, easy answer to your 18 yr olds friends problem !
A modern artwork in the form of a vase filled with numerous lengths and diameters of dowel. (Think of a bambo arrangement). Dowel comes in numerous diameters up to at least 2″. The pieces would obviously have to be sanded well to shape the ends, could be painted different colors ?? How pretty and modern 🙂 Your friend could have a different color and size for every day of the month ! Probably would wack a condom on them before use.

Not bad, but I think we can do a lot better…I’m after things that can be in a teenage boy’s bedroom that don’t look out of place, but feel good up someone’s ass…keep those suggestions coming.