In my opinion every position can be the sexiest. It's the settings that deem the level of "sexuality".
Over the lap can be very sexy, when Doc/daddy/Dom hands gently slid your panties down, slowly caress your cheeks apart and made you arch your back as they stroke you just in the right way.
Against the wall... As you lower your upper half and lean with your arms against the wall, your back arched and your legs spread. You peek from behind your shoulders and shivers as you see him approach with the glass tube already lubed, knowing what was to come... Maybe you'll have to hold position, maybe you'll have to straight up your back, place your hands behind your neck and hold the glass in place with your sheer determination as he start to touch you as he wish...
Diaper position, he held your legs up, looking down at you as you squirm under him, smiling softly at you. His hand firmly held your legs up, while the other slid the thermometer inside you. Soft encouraging words are spoken while you are forced to look up at him and feel the humiliation of the exposure...
Belly down on the bed, maybe with a pillow under your hip to lift up your bottom. He spanks you, or will spank you, or has already tanned your behind... Will give you an enema or will take you in that position as soon as the temp has been registered...
And many many many more scenarios pop in my mind just to mention a few. So again, for me it's not the position ...it's the setting. Although, I do have a fav position to assume ... 😏