[Kerun]

Ooh, now, do you want shounen-ai or do you want to go into the wonderful depths of yaoi? Personally, I didn't like Gravitation as a manga. In my opinion, you'd be better off watching the anime. As for loveless, I only watched the anime and don't know anything about the manga.

Now, there's a whole lot more range in yaoi compared to shounen-ai, plus the annoying matter of the almost no-kissing in shounen-ai, when even hugs are considered fanservice. I'm not saying to start off right away with hard-core yaoi, but some soft yaoi could be good.

I recommend on 'Yatteraneeze!'. It's this shounen-ai - yaoi, and the best one I've read, I must say. The first volume might startle you a bit [though it's not hard-core yaoi] if you're not used to it, but I'm pretty sure the other five volumes are pretty much shounen-ai. The last volume is probably considered yaoi.
If I'm not mistaken, this manga doesn't contain any specific drawing of winners hanging in the open every single page. Moreover, there's a pretty good chance that there aren't any at all, but I can't be absolutely sure about it.

Anyhow, it's one of the best mangas out there, and a pretty long one too, compared to the usual yaoi-shounen ai ones [seven volumes].

But, since you wanted short ones, I think the best solution would be to search in mangaupdates shounen-ai/yaoi and check the 'search only for oneshots' box. You'll find a lot, I assure you, though they tend to be utterly, ridiculously fluffy [but since you said you don't mind, then go ahead].

I still recommend on 'Yatteraneeze!', if you'd like some more serious stuff with an actual story line.

Lastly - if you'd like to read yaoi oneshos and not shounen-ai, then I have quite a collection if you're interested. Just say and I'll find you one that you'd like.
Hope I helped you out ^^