is it possible for coolant to leak out the open nipples when the by pass is finished????

 

Only a few drips of what might be left in the TB. Couldn't be much.

 

There is no connection to anything internal to the throttle body. The coolant from one hose simply flows through a passage in the TB bottom plate, and flows out the other side. Once you remove the hoses there is no source of coolant inside the TB, so there is no way for coolant to leak out, except any drops left inside, as Rob/Shoebox points out.

 

just take a paper towel, put it on one end and blow from the other, will get rid of the excess