you could be starting to loose your mucous plug, depending on what colour green it was, if it is sort of tinged green, then thats what I think it will be, the higher up your cervix you go the clearer the plug becomes, you could mention it to your doctor and they will probably take a swab but I think its just your cervix starting to soften and ripen and the sex may have helped dislodge some of it :)
the ONLY time green is ever good, is when someone is giving you money :P
Green could be a sign of infection...smell it (gross i know) but if it smells horrendous, you have an infection! a Bacterial Infection....easy to clear up..takes only 7 days with meds
It sounds like an infection to me, I had green discharge and it was a bacterial infection, I'd get it checked!