First, contact your 401(k) sponsor, such as Fidelity, Morgan Stanley, etc. and ask the following two questions:
1. Does my 401(k) plan allow after-tax contributions?
Unfortunately, not every 401(k) plan allows it. Hope you are the lucky one!
2. Does my 401(k) allow "in-service withdrawal"?
Again, not every 401(k) plan allows in-service withdrawals, hope your plan allows it!
If you have Yes to both questions, congratulations, you just received a big gift from IRS!
Your next step is to carefully budget your daily expenses, make sure your life won't suffer much as you stash away $50,000 each year towards your retirement use!