A.T.
It's that time, they no longer need naps and won't go down if they can help it. It is time for mom to get involved and lead the quiet time. This is now going to be the time where the 3 of you go into their room and read some books or draw while listening to low, soft classical music or watch a movie together. Set the tone for quiet time, calm time. You must be there in the beginning to establish this or they will do what they want with their time (jump on beds, make a mess etc). Be consistent and just replace nap time with quiet time. Eventually, it will be instilled that with or without you, calm and quiet is what is expected in this time period.