The act of vigorously masturbating penis, aided by either poppers, weed, or both and often at the expense of personal relationships and productivity. So named because the masturbator engaging in the monkeybate is often so overwhelmed with pleasure that they screw up their faces in a way that mimics a baboon, gorilla, or monkey.
Assuming you will have something before you actually have it; similar to "counting your chickens before they hatch" (which is commonly attributed to Aesop).
"The Mariners could do better than expected this year."
"Let's not kid ourselves. Check your premises before you make a prediction."
"I'm assuming a number of things go right. Maybe I'm just counting my monkeys before they're out of the trees."