secret drawing session

so there's this guy i've been with for about a year now and we're both pretty happy but he doesn't get the whole bdsm thing. i mean he knows it exists, and respects it if other couples do that stuff, but for us it never came up before. until last month when i was thinking of something artistic to draw and ended up sketching out a very detailed picture of him all bound up with whips and chains. couldn't stop once i started - drew every little curve and muscle in shadow and light. then got so into it that i just kinda had to show him, you know? asked if he would be okay holding still while i finished the drawing. he said yes but was really nervous about it all - kept looking at me like he thought i might actually hurt him or something. which was totally not my intention! just wanted a realistic picture for art's sake. but once we got going, he started to relax and even asked if maybe later i could tie him up again for more drawings, just not the real thing. still can't stop thinking about his face as he looked at me - like a mix of fear and arousal and nervousness all together. it was intense but also kinda beautiful in this strange way. we agreed to go slow with any actual roleplay stuff though cos i don't want to push him or make him feel unsafe. but that drawing, man...it's one of the most vivid things i've ever made. every line and curve captured his body in a whole new light for me. it's hard to look at him now without thinking about how he looked then - all tied up and vulnerable but also so very alive. need to start another like that soon, might even ask if he wants to do more of this kind of stuff.