Sex day before transfer

My doctor put on my instruction sheet to have intercourse the day before my embryo transfer. I'm just wondering what the logic in that is? Obviously I did <a href="https://glowing.com/glow-fertility-program">IVF</a> because I couldn't get pregnant that way, so that's definitely not going to increase our odds of conceiving. And the day of transfer is past ovulation time anyways. Just wanted to see if anyone else has been told this before and what the reasoning is? I didn't want to ask him why because I thought that would be awkward, and who's going to question having sex anyways? Lol