Likely its either your hips getting wider or just after sex spotting. A few drops is nothing to worry about.
I had spotting too and freaked out. Turns out it was coming from the rectal area not vagina. Asked my doc and he said its hemmoroids.
Spotting is a sign of preterm labor I would call the doctor
We did it again and I haven't been bleeding. Should I still call my doc?
^agreed. Also, unless your contractions are regular and getting closer together then you're not in actual labor yet. Could just be braxton-hicks (practice) contractions. Your doctor may advise to hold off on sex for the remainder of your pregnancy though.
When in doubt, call your doctor.