A group that loves to defend animals has issued a press release to express its opposition to "ridiculous" animal research, like the one where they poke the rat vaginas.
In Defense of Animals, some kind of hippie perv collective, has issued its list of the top ten most ridiculous animal research projects. You may be interested in the details of this one, per their press release:
Female rats might enjoy vaginal stimulation (Dartmouth)
# The "vaginal stimulation" study, which involved the experimenters holding the rats by their tails, inserting a 1 ml plunger into their vaginas until they contacted the cervix, and delivering 15 total stimulations lasting 2 seconds every 30 seconds;
# Removing rats' ovaries, giving them hormones, applying lidocaine to numb their vaginas, to find that it made no major difference in their mating rhythms;
# Severing the nerves that connect rats' genitalia to their brains, to find that they showed abnormal sexual behavior, even though they still desired sex.
There's some other stuff in there too.