In short, if you are CERTAIN your period is coming in two days, you should be fine and would not need Plan B because you weren't ovulating. If there is any chance that you wouldn't be getting your period (in other words, if your cycles are ever irregular) then Plan B might be a choice.
If your period is due in two days, you are unlikely to be ovulating now. That timing is what would be likely to keep you from being pregnant, not your boyfriend wiping off his penis.
Your boyfriend wiping himself off makes no difference because he ejaculated, and that left sperm in his urethra. The next erection he got produced pre-ejaculatory fluid in which the sperm from that last ejaculation hitched a ride into your body.
If many hours had elapsed between his last ejaculation and his next erection, and perhaps if he had used the loo a few times, it would be likely that he would no longer have any sperm in his urethra. But in this situation, there was pretty much a certainty that his pre-ejaculate contained sperm.
If your cycles are regular and if you really know for sure that your period will come two days from now, you should be safe because women don't ovulate two days before their period. But the approach you two are taking to having sex, sooner or later something will not work ... either you will not in fact ovulate when you thought, or he will do that wiping thing and it won't do any good at all and it will be at a time when you're fertile. Why not get on the pill or get an IUD?