A thing to yell during Sex to test if he/she is paying attention to you when you talk dirty. It can also be used make the other partner uncomfortable, laugh, or possibly question what the hell you are saying.
Running a tug boat means to have 3 men no more and no less than that, tugging one out (masturbating) in a horizontal line side by side all facing one chick and blowing your load all over her.
"Man that chick is so hot."
"Yeah she looks like she needs a good tug boat ran on her."
"Well boys hope you are ready to tug one out, let's fuck up that pretty face of hers."