Okay So Just Too Make It Straight What is MY Part In These Situations ?? x 10POINTA?

Okay so me and My Bf Havv been together for most of the school year (High School Btw) And it took us a VERY VERY long time to actually talk too eachother like Bf&Gf. I really don't know why, but it was just something that did't click. But NOW it's ALOT better, we kiss, and hug and hold hands and all of the lil cutee things and we now hang out alot together, but still pretty frigid, I havv no idea whyy because there's no reason too be because we love eacother Soo much. But today, I was sitting on the South bench, talking to my friends and he came up behind me (he was standing up) and put his arms around me, like so his hands were jus' abuvv my ""Chest"" If u get the drift, but I didn't know what too do ? I haven't really hadd THAT MANY guys in the past, because I don't say Yes unless I think it will last for a good amount of time, and obviously this has, but anyway Yea he put his arms around me near my ""chest"" and we just stayed like that for ages, and it was really nice :) but I didnt know what too do? Like do I turn around and hug him ? Take his hands? What should I do or what would YOU do ? I didn't mind his hands being near my chest atall FTR haha ;) . So Anyway yea, What should I do next time and what do I do if hes standing behind me and I want him too do it ? Jus get his hands and put them around me ? 10 POINTS MOST HELPFUL ANSWER ! Thanks x x