A sexual act in which the arm pit is used to give a hand job to a male partner. The arm swings back and forth like the person administering the job is rowing a boat. Two people receiving can be used to accomplish a full rowboat effect.
"Martha's shaved arm pits sure made for a good Columbus rowboat last night."
A line of men jerking off the person behind them while yelling, "stroke, stroke, stroke". Colloquial term for a circle jerk but there is one asshole leading the March.
Sorry to interrupt guys, I didn't know the party had turned into a Swedish rowboat.
Phyllis: Michael, I want to set you up with my friend.
Michael: Hm, what's she like? Is she rowboatable?
Phyllis: What are you asking?
Michael: I think I'm being very clear what I'm asking. Could an average sized rowboat support her without capsizing?
(pause)
Phyllis: No.
(Michael walks away, disgusted)