We've never done penetration. The only reason why I'm paranoid is in this one instance, she is giving me a bj and then she said she can taste c*m so I presume it's a precum but then afterwards I fingered her. So I'm being paranoid is that what If I touched the precum with my fingers? and then inserted that finger to her vagna? I CANT REMEBER! But the only thing rest assured is that we've seen no cum cause I've never cummed on that instance I mean we've finished our sexy time without me cumming because my sister came into our house and that's why my gf needs to leave. and I've read this too in this site with similar situation "Precum does contain a SMALL VERY SMALL amount of cum.. Its like only 300 out of 700million cum. Once your precum touch the air, that 300 will reduce by 150 OR LESS. To be honest, your more likely to kill the president and win the lottery than getting pregnant from that." Is this true?