My friend and her boyfriend were having unprotected sex & he pulled out & jerked off for about 2 minutes and then he came. she played with his penis for about 5 minutes & they kissed & did their thing for about 5 minutes until he inserted his penis back into her vagina. she says the semen on his penis was dried & she couldn't see it anymore. she's worried because of all these myths about how long sperm can survive exposed to air. please answer quickly because she wants to know if she should take the "morning-after pill" thanks!