We say: absolutely not!
Nobody is themselves to blame when something like this happens.
Nobody may touch you if you do not want them to.
Sometimes there are silly moments.
Even with somebody you know!
Sometimes it was a nice night to start with.
But then something happens which you do not want to happen.
But what always matters is that your feelings are correct and important!
Even the law states:
Kissing, touching and sex with a partner who does not consent to the activity is forbidden.
Even if you couldn’t properly express yourself at that moment.
Even if you are too drunk to say no.
The other person will still see if you are really enjoying their behaviour or not.
You can always seek help.
For example, in Munich we have the IMMA advice centre: http://www.imma.de/einrichtungen/beratungsstelle/kontakt.html
Young people can find help elsewhere in Germany here: https://www.zanzu.de/de/hilfe-beratung