Aaannnddd.. he does it once more in chapter 263. It's even extra clearly sensual. This trope is a holdover from when it was even now considered risque to clearly show a male and a woman in the same mattress (even if they ended up married). Then there is a lovely scene from the manga in which The Baka Makie promises this trope but Negi is of Improbable Age. This trope is affiliated with Hisoka to varying degrees. Hisoka actually likes combating.