Im not used on doing critiques , but if you allow me, i would like to share my thoughts about this pic.
a)The angle/perpective. It gives the character a little more dinamic while she try to tease you by pulling down her panties. A good perspective can raise double your work and i think this one could be the case.
b) Your color technique is really impresive. Somehow its seems very simple but im sure that is not simple for you to color like this. Little advice: try to blend some of the lights and shadows according to the enviorment instead of using only the standar -sking tone that you usually use.
a) the expresion. She is somehow in like a "neutral or serious mode" for what the pic really wants to show " Teasing, sexy- concept". I think you should work more on your facial expresion in order to match the concept of what you are trying to show.
Indeed its a very good-quality pic but it lacks on emotion or feelings. Try to work more on those concepts on your next work, i wil asure you the results will be even better -
PD. i hope you dont take personally this critiques, im trying to help