So here’s a little turtle position training on the Submission Master grappling dummy (available from https://grapplingdummy.net )
The easiest way to get the grappling dummy in turtle position is to sit him up in guard, then pull him forward.
The first technique is when you have your leg hooked in on his close leg and can’t grab his wrist. Pivot backwards, pull both ankles toward you and lay back. Discard one leg and pull the other for a knee crush.
The 2nd technique is also with the close leg hooked. Reach over top and grab his far wrist, lay back and take the back position.
The next jiu jitsu technique is when you have your leg hooked in on the far side. You grab the grappling dummies wrist on the other side of the hooked leg, post your arm, put your leg in front of his head, roll and kick your leg back for arm bar.
The last submission technique starts with the same position as above but hook his arm with your other arm, your shin goes behind his head, and roll for arm bar.