You'll often find yourself in these rides when you're taking down your opponent from neutral. We highly recommend that you look for them in this case, as you'll be able to get a few quick back points with the takedown if done properly.
Otherwise, you can get these rides by going far knee, far ankle when starting on top. With the Navy, it's important to keep your arm as close to the crotch as possible and keep your elbow on the mat, so he can't weasel his top leg out. Be ready to switch your grip between the two and keep your hips into his in case your opponent decides to roll to the other position.