Not to mention that

a) going under the plaintiff's outer clothing very clearly moves the onus of demonstrating that it was accidental back on the accused's side, because no reasonable third-party can accept that you can accidentally slip and fall into someone's pants

and

b) the accused admitted that the action was intentionally non-consensual, but their defence was that the motive was non-malicious

Even before we look at the duration, there are other factors that make the case way more clear-cut than this judge thinks it is.