Could you be pregnant if your boyfriend pulls out and cleans the tip of his penis and puts it back in?

That's not a very good idea. Before ejaculating a man releases what it's called precum. Normally precum doesn't contain sperm but if there's been a recent ejaculation, some of that sperm might be trapped in the urethra. If that's the case, that extra sperm might come out with the precum (which guys can't tell it's coming out) and there's a chance you can get pregnant.