What sharks is the unexpected. I've seen serious games with two or three people leaning on the table. That's what everyone did there. If I get up from the audience and lean on your table to see the shot better, I imagine it will bother you.
There are "virtual" sharks. Concede some easy nine balls -- and then when one is slightly tougher, get up as if you are going to concede and sit back down.
In McGoorty, Danny tells of the virtual shark an old Alfredo de Oro did to Cochran:
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And here is some more standard sharking from Alfredo:
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