DD was just over 2. She still wanted us there, but she really started to play up to try and get us to engage with her and us being there was ultimately keeping her awake as she couldn't help herself but to 'fish' for a reaction. We started doing 'rapid return' - going in and out quite quickly, then gradually spaced it out so we were away for longer periods. Now at 3.5 we go back in once after 5 minutes for a last kiss and cuddle and then we don't go back (except, of course, if she genuinely needs us and doesn't just have a terrible case of 'bumpy pillow, need a tissue, need another drink, need to ask you a question...) - she's still fishing!
Exactly that.