I can't say I have ever noticed "underage stuff" anywhere in Thailand, now or in the past. Obviously I find myself in a somewhat different milieu to Trongpai when in Thailand.
However, for example at boarding school it was common for an older boy with body hair, facial hair was the ultimate, to get a junior to suck him off after lights out or just anyone with a shorter shaft, these were my first encounters, I wonder how legal that is. I have yet to see a sixteen year old being arrested for getting a 14 year old to wank him off in the showers, maybe still to come?
Don't you think those shoes look suspicious, that or the artist decorating the vase had a sudden flash into where sandals where going to end up?