First time

Have had an Aneros for a while and done a little with it but not much. Today was the first time that I actually set an hour aside to experiment, relax, and see what happened. I laid flat on my back and tried to do nothing but lie still and breathe. I noticed that when I lightly clenched everything it felt good so I started doing that very gently while I relaxed and kept breathing. About ten or fifteen minutes in, I noticed it started feel like a small spasm inside me. After a few minutes, that spasm became a little more intense and pleasurable. The only way that I can describe it was that it felt like it was pulsating when I clenched up. I began breathing a little harder and noticed some fluid coming from my dick. The pleasure only lasted a few minutes between moving and getting distracted but was enjoyable. What was going on and where do I go from here?