You might think that the physical challenges of being on all fours and the mental leap into pupspace in your head are the big hurdles in human pup play. They aren't. You can learn those things over time. The hardest hurdles to get over are the ones that require you to unlearn, to stop doing things that you have been doing naturally for decades. One of those is making assumptions.
Making assumptions can strain your relationship with your owner and trainer and other pups as misunderstandings occur. By thinking that your master or a pup is going to behave in a certain way before he has even had a chance to act you are making assumptions which can cause trouble. Big trouble if you are in pup mode and you don't want to break the mood.
You can't avoid assuming because your mind works like that. You can pay attention to how you assume things regarding your master as knowing how your assumption works will make it easier to avoid pitfalls associated with it. The truth is that even when your head is in pupspace your brain will still make assumptions. It's a critical human capacity you just can't lose and still function. Anticipating problem situations, your human mind assumes things - such as the fact that being on all fours means you move slower than your master on two legs. You assume this and it helps you formulate a response if an unexpected situation arises - such as your master having to run across the hall, needing you to follow. You automatically follow through on that assumption that it's probably an emergency and getting up off all fours to run on two will work better for you.
Assumptions lead you astray when you stereotype people; that is when you assume that anyone who is from a different group than you - whether it be race, gender, sexuality, age - behaves and thinks in the same way as the whole group you have classed them into. These stereotypes are your own bias pup, and they often offend others and discriminate against those people being able to participate equally and fairly in pup play. Common stereotypes are often just based on ignorance as a person doesn't know what the hell they are actually talking about since they haven't dealt with or been educated on the matter. Some common assumptions that are wrong and will lead you astray are that all Alpha pups are sexually dominant and don't want anal sex done to them - the gay scene calls this type of person a Top - rest assured if it comes with a hanky and a term its a stereotype. Another is that women prefer to be feline and kittens rather than pups. Of course the most pervasive of stereotypes is that all pups are submissive. You can avoid stereotyping others by dealing with every person as an individual. Get to know each person you deal with in pup play and make an effort to understand them. Doing this will improve your communication with your owner and trainer and others pups, as your healthy dealing with pups in community pays off in your private sphere when you bring your increased learning of others ways of doing things and their unique experiences to your pack. You may note that this very article is offensive to women as it assumes pups and masters are male. That's how stereotypes can creep in and become accepted standards.
Often you can find yourself in difficulties with your owner and trainer when you assume that your master has intentions behind his actions that are actually not true. This goes very badly when you assume the worst and get anxious about your masters "assumed" intentions. It can be something as ordinary as you seeing your owner being friendly to another pup and you assume that you are no longer cared for as much as you were a moment ago. These assumptions cause annoying and often very detrimental outbursts from you as you find yourself carried away by the assumption and start acting on it. By focusing on intentions, on why you think others are doing what they do, you can often go very wrong pup as you find yourself interpreting minor and inconsequential actions as being terrible and potentially devastating. A molehill becomes a mountain becomes a big hurdle to enjoyable pup play.
The easy way to avoid this shit happening is to ask questions. Of course, the way you ask is also important. Avoid passive aggression - no one likes being guilt tripped or sulked at. Speak respectfully and with care to whomever you need to clear something up with and it is likely to go fine. Listen, actually listen, and absorb what is being said. Don't jump in and challenge what you hear because you are upset. Be a good pup and control yourself and use the positive power of assumption. Assume the person means well. After hearing what was intended - or not intended - move on. Immediately begin to do something else and have fun. By dealing with and accepting others in the pup community at face value you will be a friendlier pup who is socially welcome. It's important to avoid these emotionally destructive assumptions by engaging with others and asking them the rationale behind their actions. Deal with the facts and not your assumptions and that grounding in reality will help you function better in a bdsm scene that is very heavy on the roleplay and nuance.
The general rule of communicate first, act second will always help with assumptions. Check with your owner and trainer, ask other pups in the pack, question and inquire. That way you can coordinate your effort at pup training. If you find that you don't know something, admit it to yourself, and try not to assume anything. Ask, listen, learn and you will become a better person and pup.