The depression medication Zoloft can be very effect and sometimes it makes male users appear very happy down there. Much like Viagra, Zoloft warns of “persistent and painful erections”. The only difference here is that you may not actually have the happy ending associated with Viagra. Zoloft also warns that “ejaculation failure“ is another side effect of the drug. That means you will be walking around with a rager and no way to make it go away.