Not sure where you would find it exactly...but the torso is most likely a 9x13 cut and shaped. For the penis you would probably want to go with RCT or something along those lines.
If you look at my pictures, you can see the one I did. Mine is a female, and the torso section is a 8x8 but might give you an idea of what you want to do.
I've done a female torso too, carved from a 9x13. The male torso wouldn't be too different except that you wouldn't carve it in as far on the sides and of course you wouldn't put the cupcakes on top 
You could put some strips of fondant underneath the top coat to build up the pecs and to look like a six pack.
You could make the penis out of a piece of cake...if it needed to be standing up, then use a wooden skewer to hold it up (but warn the person who ordered the cake, there's a certain way that people usually eat naughty cakes and you don't want the bachelorette to break a tooth!)
Where would I get the design for the male torso w/ penis?
Go to the cake galleries, use the search button (same line as "album list" and "upload picture"). Search word "torso", and filter (search by category) using "naughty cakes>male anatomy.
HTH
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