My bf and I recently purchased two female? mice from Petco. For the
first two days, I only opened their cage to give the new food, toy,
or water. However, on the third day, we took them out of the cage
to change some of their bedding. I think that my mice are royally
p'ed off at us for having handled them. The more extroverted one
now drums her tail against the cage whenever she sees me. Does this
mean that she's scared of me? How and when should I try to tame my
mice?

Also, um, we've noticed a peculiar bulge underneath their tail. I
don't want to pick them up again yet to examine the distance between
anus and genitalia to sex them. We specifically requested two mice
from the cage marked "female" because we wanted to avoid fighting
and the musky odor. Our mice get along well. The larger, more
extroverted one will occasionally dart after the other. But no
squeaking, no fighting, no blood. And there's a mousey odor, but
since we've never owned mice before, I don't know if this is musk or
a urine/poop smell. No matter what though, my bf and I have decided
that we love our new snuggle mice.