
Written by Eoghan O'Connell on 05 Nov 2025
Distributor J18 Publishing • Author/Artist 23 • Price Free
You would think that one of the worst things about reviewing products is coming across something you hate. However, the truth is that the one type of product that I most dread having to cover is something that I feel completely neutral towards. If you dislike something, you can at least elaborate on why you dislike it. Having to explain why you feel so little towards a product on the other hand…that’s hard. Having said all that, you’ll probably see what that little rant was about, let’s take a look at today’s subject, the doujin Training Day by 23.
The story is that a coach at a gym is helping a heavy man lose weight. Once he has finished his training, he’s surprised to learn that the gym provides some post-workout “exercises” to refresh their client.
That’s pretty much it. The doujin has a little gag conclusion to end things on a funny note but, otherwise, it’s just an excuse to watch a fit, well-endowed woman have sex with a heavy man who gets progressively thinner and more muscled throughout. I don’t want to sound too critical because I’ve definitely read worse but I felt absolutely nothing upon finishing. I didn’t feel happy, sad, angry, confused, just indifference.
As for characters, there is very little to discuss. We aren’t even given their names, leaving me to refer to them as the client and coach. The client seems to be an earnest man who genuinely wants to become fitter, a fact reinforced by his surprise when the coach moves in to do his post-workout “exercises” with him. Besides that, we know nothing else about him. We don’t know his motivation for working out beyond a basic drive for fitness or how he missed the gym’s seemingly obvious “exercise” policy. As for the coach, all we learn about her is that she’s good at her job and that she enjoys sex. That’s all. I do think that the severe lack of character development, whether that be throughout the story or even simply establishing their personalities and motivations, is a big part of why I felt this manga left my mind as soon as I’d finished.

Given that you’ll clearly be reading Training Day purely for the sex scenes and art, how do they fare? Character designs are simple but work for the most part. The coach is a tanned, fit woman with blonde hair whose enthusiasm for her job radiates from her expressions, the shots of her licking her lips perhaps being an obvious sign. Besides being a little on the generic side, my biggest criticism of her would actually be her proportions with her breasts being a little too large and, dare I say it, unconvincing for my tastes. The client is even more generic, looking like a heavy young man with glasses before transitioning into a muscular young man without glasses. The backgrounds aren’t very detailed but there’s some nice paneling alongside some good visual angles.
In the end, what we are left with is a work that revels in its sexual scenes with hardly any story or character development. That’ll suffice for some people but it hardly makes for a memorable experience. I would even argue that there are better examples out there, the first chapter of Imaizumi springs to mind, that manage to focus on sex while providing a smidge of character development that enhances the experience. Training Day may not be the worst doujin that I’ve read, far from it, but it is certainly the least memorable so far.
You can read the title for free on doujin.io.
Going by the online persona Immortallium, I'm a YouTuber as well as a Manga, Anime and Video Game enthusiast.
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