I can tell you from experience, they won't notice. I have always been a sucker for the 'fart joke'... In any particular form. I'm pretty sure its 'Little Brian' who has me splitting sides whenever I hear even the smallest of squeakers. It's an area in which I feel like I've NEVER grown up.
As I mentioned earlier -- experience. This has been going on for a really long time and I can tell you now, no one is anything the wiser. Even if you were to act on these impulses you feel.
I have spent years doing just that. It is just recently that I'm recognizing the inner child and recognizing how 'visible' he has been all these years. Fart jokes is one area. Other things I oftentimes find myself doing is 'random word greetings'. This is where, instead of saying 'hello' or 'hi', I go for the much more fun "hell", "assmonkey", "mooBANG!", or "honk" as a few examples. I have learned now that this is just another way I have 'played' all these years without even thinking of what was going on in my own mind to provoke this. I think its exceptionally similar to what you described here.
I also know I'm usually very uncomfortable with 'new people'. Something worth noting is that... this is when my vocabulary of the bizarre kicks in the most.
Anyone want a thumb war? 1..2..3..4..I..Declare..