The Rocking Horse position is a variation of the rider-on-top/cowgirl position.
To get into this position, the penetrating partner sits on a flat surface. They may need to lean backwards, resting on their hands, to give the receiving partner space to sit on top of the penetrating partner's lap. The penetrating partner then straddles their partner's lap.
This variation of rider-on-top can be especially appealing to people having penis-in-vagina sex who also enjoy anal stimulation as it leaves the receiver's backside free for anal toys like the Blush Temptasia Bling, Rocks-Off Cocktail, or b-Vibe Vibrating Jewel.