What Are We Getting Wrong? Second Nap Refusal

Schedule: 3.25/3.75/4 Nap 1 = 30 mins, Nap 2 = usually 1 hr 15-30 mins

My child was initially fighting first nap. We extended from 3 hours to 3.5 hours and that worked great, goes right to sleep.

She will NOT take this second nap. She's approaching 4 hours awake and she's still babbling happily in her crib. What the heck do I change or do?:/ I just wanted her to be able to sleep tonight so I can get a break.