Slamming legs on mattress??

Sydney • 26. Army wife of 6 years. 🇺🇸 Momma to 1 angel baby 👼 and 1 earthly baby AJH 💙 02/18

My son is 17 wks and he used to sleep like a perfect little angel from 830-530.But lately he sleeps well from 830-130 but then he starts to kick his legs and slam them onto the mattress. He doesn't always wake up when it happens...but I do 😑 bc it's loud.

Anyone else's LO do this? Any tips or advice?