I was going to suggest the same as Christine...right before work, right after work and at bedtime. As for how far in, i would try to get it as close to the cervix as possible. I used prometrium vaginally once after an IUI (and crinone in my IVF cycle), and that's what I did. And yes, I would wear a pantyliner, because it can cause some creamy, yellowy discharge. Good luck!