Yup totally agree with Clysta...walk walk walk, sex...bounce on a birthing/yoga ball if you can...but I lost my mucus plug at 30 weeks, then it grew back and I lost it again at 37 wks...and was induced at 39w4d....similar with my daughter and she came on her own at exactly 40wks.
Unless your water breaks, intercourse is fine. However, losing your plug isn't a good indicator of when/if labour will happen on its own. My advice is to walk walk walk.