From a school mate:... Pulling out before cumming is as safe as using a condom...
well, it definitely needs lots of concentration and somehow lessens your pleasure and let go to some extent, but sometimes, you can miss and it's not safe at all!! but for some men, and some women, having sex with a condom, for some reason is much less pleasurable, and if the man is okay with pulling out and is sure he will not forget or something, it can be a good advice somehow!!