Don't under estimate your 2 year old - he understands a fair amount of reasoning at this point! You really need to be firm and persistent. Studies show that it takes 21 days to create or break any habit. So, you need to be extremely firm for at least 3 weeks - that includes a strict bedtime routine plus ensuring that you return him to his bed each time he crawls into yours. It might be a tough couple of first days, but it will be worth it in the long run. Also, your little one should be in bed by the latest at 7:30pm each night. The longer you leave him, the more "alert/overactive" he will become and he will resist going to sleep more. At his age, he needs about 11 hours sleep per night - so you do the maths. Make sure that you are very loving during his awake hours but take the time out every evening to bath him, read him a story and put him into his own bed. You could even start a reward system - nothing too complicated - and build from there.