1st one references late wittgenstein's views on mathematics, were 'mathematical truths' are invented, not discovered. the 'rule' is created after the fact to account for the invention
the 2nd one is in reference to his war time diary, where he records jacking off while thinking about maths. (it's possible he actually jacked off to Dudes, but didn't want to put that in his diary)
3rd refers to this bit in 'on certainty':
@esvrld these are fucking brilliant
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