It is very unlikely that syphilis would be passed by the activities you have described, this is not how we see this bacteria being spread.
Syphilis is usually passed through vaginal, anal or oral sex. It can also be spread through genital to genital rubbing. As there was no genital contact during the lap dance syphilis would not be passed.
For more information on how this bacteria and how it can be passed check out our Syphilis page.
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