How do I let my wife know I need to be taken care of in the bedroom without being a nag or whinning?

I've been married for several years, we have three young boys and a teenage daughter. I've worked at making sure she is not overburdened with the kids so that she is not too tired at the end of the day. I am very good at communicating with her when I would like to "do the laundry together". She however, sees this as nagging her for attention. I've tried to not ask at all which results in zero attention between the sheets. Any suggestions?