Anything that comes graphically close to exaggerated pregnancy gets a sniff (with some justification) from most adult women and a belly laugh from the junior set. Mother, Mother I Feel Sick (299-J-95) got quite a going over for this quality in oral review sessions. However, this book is for very young children and it tries to make the point, in captions and illustrations, that swallowing interesting things is an uncomfortable habit, as many a three year old knows (sometimes secretly). Aliki's little alligator, like Waber's Lyle the Crocodile, has an expressive, mobile face. He's also got a big mouth that everything, including an alarm clock, falls into. His parents tried various ways of lashing his lips together, but the little fellow got more and more bloated and his bulging belly clanked and ticked. Finally, the vacuum hose fell in his mouth and sucked everything out. Shudderingly extreme? For dainty adults it is. But for early childhood, it plays straight to their often shattering sense of the comedy in anatomy.