You don’t always need to work on getting back to guard or executing an outright sweep when fully mounted. An alternative strategy is working on a transition to a single-leg X-guard.
Begin by securing the opponent’s arm using a cross grip and bridging out. This will cause the opponent to base out with his free arm. This leaves an opening for you to get into the X-guard. From here, you can drop your weight to one side and go for an Achilles lock. The other option is to push out the opponent’s free leg. This enables you to get your opponent down as you stand back up.