Hi, So I Have Sex With My Wife And Everything

Hi, so I have sex with my wife and everything is fine, next night, less then 15 seconds in and Im having trouble getting full insertion and then I feel like this sharp pain so I pull out and I have a scratch on my penis with min blood. My wife says nothings up there and she has a vibrator. When I was like wtf she says its not me and I got no Vibrator in there or anything. next day everythings back to normal. My question is she says she is not doing anything at all and its her body doing it against her knowledge. not sure but I don't think a vagina an all of a sudden scratch me but a vibrator or something un natural could. Is what she says possible or am I crazy?