Brazilians do something similar in that they inject both silicone and/or saline into the base of the penis, as well as into the actual scrotum, in order to experience temporary engorgement of the penile shaft.
The good thing about saline is that it typically gets absorbed well and is not toxic to your body. The same, unfortunately, can not be said of silicone. In any case, attempting to do either can be very dangerous, especially if done under conditions that are not sanitary/sterile. Said practices can lead to severe infections that can very well end up with penile amputation.
It seems that some of these folks go a little overboard with saline or silicone injections into their penoris and end up with what looks like what Mr. Viking1 posted:

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