What happens if you used a condom and the guy came twice while the condom was on?

The purpose of a condom is to avoid during coitus, the transmittal of the male's seminal fluid into the female vagina, thus allowing coupling but preventing pregnancy.

One concern is that in order to avoid such transmittal, the condom must remain taunt around the male's penis. If after one ejaculation, the penis becomes less rigid, "leakage" may occur onto the condom and then if copulation continues the "leaked" seminal fluid may be transferred to the vagina.

It might be advisable to change condoms after each ejaculation.