aXio;1100285 wrote: It shouldn't be that loose that it falls out of the bulkhead that easily on it's own. Sounds like you need a new fitting. Silicone is always an option but it will be very annoying to get the stand pipe back out if you ever find the need to. Ideally you never want to glue or silicone the overflow plumping.
Typically there should be a nice "snug" fit between the drain pipe fitting and the bulkhead.