The first & probably only "classic" rear entry position is the Doggy Position.
While you are in the doggy position you may want to try what is known as "riding the pony". ...
For even deeper penetration the woman may fall into a Resting Position. In the resting position the woman stays on her knees but lets her chest and shoulders to rest on the bed....
The Rear Half Squat is a great sex position for any occasion. With his legs under him, kneeling, she kneels in front of him with her legs just outside his....
The Rear Squat requires a tiny bit more agility but offers the couple a wonderful position for what we like to call a "slow grind"....
For something more comfortable for her try the rear resting squat....
A bit trickier but no less exciting is the Laying Rear Entry position. With this sex position the woman lays flat on her stomach, spreading her legs just enough to allow him insertion....
One way to add further penetration to the above mentioned position is for the woman to slightly roll her hips upwards....
Not exactly a rear entry position but close is the Kneeling Leg Over Position. This position adds some wild sensations to both parties as the positioning of the man's penis is somewhat sideways....
Taking this principle up one more notch can really ad fuel to the fire. The Side Saddle Position can add some great penetration & a super tight fit that makes this the one that always seems to please....