Spanking or Over the Knee is one of those simple overlooked activities for a scene. To me it offers an intimate connection, a more controlled impact experience, and the opportunity to explore vunerablility.
A good scene starts with a warm up, a slow caressing of the ass, progressively turning into a heavier massage. This helps relax, build trust and blood flow to the area. It also creates a bit of arousal, a lovely state to start any impact scene. Next comes the slow rhythmic open handed slaps, that merge into massages. Once warmed up your bottom can start taking the heavier blows. Think of it as music, with a slow build up to crescendo. Having music playing that goes along with your rhythm is a great idea as well. At some point, the really heavy, fast blows come. After a hard hit, take the time to let the bottom process, slowly caressing the area before starting in again. I also enjoy unexpected hits outside the area, like thighs, or upper back. I may also press my body against their's to ground them and dominate them. A slow wind down includes and ends with gentle rubs and caresses. And ends with whatever aftercare was negotiated.