Hi your Jyotirmoy
A Batty Snail is a type of person that is an apsolute idiot when it comes to any general thing, they are usually relatively dumb and think they are smart when they are the opposite.
Biddy, or Biddies in the plural, normally meaning a women's breast, but in this case, depending on how it's used it can also refer to a very large man's breast, or, boy tiddies. In short, Biddies means tits but for a fat man.
"Wow Alex, you fat bastard, I can see both your Biddies from here"
or
"Damn you need to lose some weight Alex, you're starting to grow a Biddy or two"
or
"Damn you need to lose some weight Alex, you're starting to grow a Biddy or two"