Hi,
Pull = attract a member of the opposite sex (ie "pull" them to you by your attractiveness)
have slept your way into university = (implies have sexual acts in uni?) No, it suggests that you gained admittance to university by sleeping with someone who has influence over admissions.
Context:
She told the Observer: 'It was hard not to take personally comments such as 'When does your work experience end?', 'You must have slept your way into university' or ' sorry Polly - we would invite you along, but we're planning to pull tonight.' With this last one, apparently men are refusing to socialize with Polly because other women might not come near them if they are already with a woman.
Best wishes, Clive