Have you looked for it on the scenes gallery ? I think you should play the scene that has this CG directly from there. I think that's how I unlocked it.
Finished Hozumi's good ending route from Suito wa Hakumei. The romance was much better than in his normal ending route but it only started towards the end of his route and thus there wasn't much of it. Also the plot of his route really sucked. The main villain of his route was an irrelevant NPC...
I found Asuma's (the redhead) route pretty boring overall but I did like Shirasu's, tho a certain plot point in his route did disappoint me. I haven't played the other 2 routes yet but I do plan to play Taiga's as well eventually.
Maybe Kintouka even tho I haven't even finished a single route from it lmao (I dropped both of the routes from this VN I've played with one single choice left till the end in both of them). I think the longest BL VN I've finished a route from is Shingakkou Noli Me Tangere, tho most Holicworks...
Favorite: "Bad boys" types who end up becoming whipped for the protagonist (however they can't hurt the protagonist too much before that happens). Least favorite: Any r*pe dynamics, even if it's the romanticized one where the uke is secretly into it/ends up liking it by the end. (I can tolerate...
The 2 BL VNs I'm playing currently Tokyo 24-ku and Suito wa Hakumei are more vanilla compared to other Japanese BL VNs, I think all of the r*pey stuff is in bad ends only. And while technically it's an Amare (choose MC's gender) and not BL I'd definitely recommend Bewitching Sinners too.
Kaine from Dreambound is an overprotective Yandere and Riou from Haiiro no Arcadia is a manipulative Yandere. (The second VN is in Japanese only so hopefully it's not gonna be an issue for you).
Well I mostly enjoyed Kouichi's second half of the route as he acted much more gentle and respectful in these sex scenes and there were actually fully consensual. Riou's route was more meh for me overall but he also seemed to act better in his last H scene after his lying got exposed. And well...