A condom can slip off for various reasons, such as not being properly rolled on, or more often, as a result of not removing the penis from the vagina right away after ejaculation, when it is no longer fully erect. Sometimes, it’s simply a matter of size. For example, if the condom is too large, it can slip off more easily. In any case, this situation can be compared to that of breaking the condom – sex is no longer protected, and you will have to resort to emergency contraception.