The rangers fall in some green goo and Dale comments that it actually tastes good, "kind of limey." To which Monterey Jack gets offended and says "watch who you're calling names boy-o!" "Limey" is a derogatory term for a British person or, as is more likely in this case, for British immigrants to Australia or Australian sailors. Since Monterey Jack has an Australian accent and is an Australian Mouse, he seems offended by Dale's use of the adjective, "limey."
The episode features a more-adult joke than most in the series. When the rangers are struggling in some green goo, Gadget inflated a hot water bottle. Visibly embarrassed (she blushes) she remarks "it never hurts to be prepared." This is most likely a reference to menstrual cramps, as young women often use hot water bottles to alleviate the cramps. That would explain Gadget's embarrassment at having produced the hot water bottle.