When you're visiting Wat Pho, look for the Thai Massage Medical School. It's located on the grounds of the temple, and I am not exaggerating - this was the best message ever! I've been back twice, and each time I walk away saying to myself, wow! They offer full-blown classes if you want to learn.
You can also just get a massage from one of the students. 60-minute massages (all in the traditional Thai style) are around 400 baht. You can also ask for a 'clean' sheet for a little extra, which I recommend.
What's great about the experience is that the massage is given on an outdoor platform, shaded, but still with views of the temple grounds.
And honestly, I am not kidding, I've had dozens of Thai massages in my life, and this is the best. Don't be intimidated, don't think too hard - just do it! It's one of my fondest memories of Bangkok.