This is by 吉富昭仁/Akihito Yoshitomi. He has published a variety of manga and had some of his works adapted into anime, but in my opinion his greatest achievement is “BLUE DROP ～天使の僕ら～”, not to be confused with the other Blue Drop titles bearing different subtitles, a short (2 volumes) and light hearted manga series which, whilst staying firmly on the side of mere ecchiness rather than being actually adult, nevertheless manages to approach much more explicit material with the perverse situations and demented story premises on offer. A thoroughly enjoyable, if a little bizarre, read; I reproduce a few interesting (H) parts here.
His other works don’t seem to approach this level of playful ecchiness, unfortunately.
It doesn’t actually get much more steamy than this (admittedly this is quite steamy), but perhaps that just serves to further increase sexual tension?
Something for everyone?
If you don’t want to read it in Japanese (it even has furigana), there are also scanlated versions available through the usual channels, so there is little reason not to check it out.