I don't think that "bong" in this sense is in the Leo dictionary:
bong1
noun
A low-pitched, resonant sound of the kind made by a large bell.
‘the clock had struck the hour and it was only three bongs’
https://www.lexico.com/definition/bong
Also
bung
verb [transitive]
1 British informal to put something somewhere quickly and carelessly
Bring me another beer and just bung it on the bill.
a. to throw something, often carelessly
Bung the ball to me, Jack.
https://www.macmillandictionary.com/dictionar...
For this Leo does have etwas irgendwohin schmeissen.
Of course the noun bung can mean a bribe.
#1 Nowadays a bob simply means a small amount of money (though, as some of us have said recently, "a few bob" can mean quite a lot of money).
#2 der lautmalerische Aspekt
I suppose one could just possibly make that claim in this case. But Boris can never resist creating an alliterative phrase.