As my life is quickly running its course, I think back on the 20 years I spent with my original Teachers and think how incredibly lucky I was. These days, it is rare to find situations where one can be with and receive guidance from their Teacher on a daily basis. If one is really serious about making progress on the path of the Buddhadharma, it's imperative to spend as much time with your Teacher as possible. However, it's also important to know how to behave with your Teacher in order to get the most out of that time. So here are some pieces of advice from the great Kunkhyen Longchen Rabjampa on how to deport oneself with one's Teacher.
"Worthy students are trustful and highly discerning, diligent, conscientious, circumspect, and knowledgeable. [They] do not contravene [their Teacher's] word. [They] observe their obligations and commitments and are controlled in body, speech, and mind. [They are] compassionate and deeply concerned about others' wellbeing, accommodating, patient, generous, and insightful, steady and deeply devoted. [Moreover, they are] always mindful of the Teacher's qualities. They do not look for faults [in their Teacher] and, even if they see them, will consider them as [hidden] qualities. By thinking from the bottom of their hearts that these faults are certainly their own [mistaken] views and not existing in [the Teacher], they use admission [of their own shortcomings] and self-restraint as counteragents [to their error].
"They reject everything that may displease the Teacher and they make every effort to to please Him [or Her]. They never go against the Teacher's word and treat those around the Teacher, even if they are on good terms with them, as the Teacher. They do not take the Teacher's servants as their disciples, but will ask them for explanations andinitiations.
"In the presence of the Teacher they restrain themselves in body speech and mind. They sit with their legs tucked under and do not turn their backs to Him [or Her]. They show a smiling face and do not cast angry glances nor frown upon [their Teacher].
"They will not speak rashly. Neither will they tell other's faults. Nor will they use unpleasant harsh words, [and] they will not will speak thoughtlessly nor at random.
"They will not covet the Teacher's utensils, and they will dismiss all kinds of harmful thoughts that are like claws. They will not judge as wrong and mistaken the Teacher's various actions and devices because that which is openly done seems to belie the hidden intention. They renounce erroneous views that carry with them the evil and defect of finding fault with everything, be it ever so small, thinking that this is inappropriate, but He [or She] is certainly going to do it.
"When they are cross with their Teacher, they will certainly examine their own faults, admit them, and restrain themselves, and, bowing their head, they will sincerely offer their appologies. Thereby they will please Him [or Her] and quickly achieve their aim.
"When they see their Teacher, they get up and greet Him [or Her]. When He [or She] is about to sit down, they offer [their Teacher] a comfortable seat and so on. They praise Him [or Her] with a pleasant voice and keep their hands folded [in namaskar mudra]. When He [or She] walks about, they follow Him [or Her] in attendance and show respect.
"Always mindful, conscientious, and concerned, devotedly and meekly in awe, they stay with [their Teacher]. When near the Teacher, they are bashful in body, speech, and mind like a young bride, not strutting about or being indolent, not taking sides, not flattering, not deceitful, not hypocritical, neither publicly nor privately showing affection or aversion to [the Teacher's] near and distant relatives.
"If they are wealthy, they make gifts to the Teacher or, by body and speech, will serve, honor, and respect Him [or Her]. Dismissing their [own] preoccupations with this life from their minds, they please Him [or Her] by their individual achievements.
"If others speak evil of [their Teacher], they refute their allegations. If they are unable to do so, they think again and again of [their Teacher's] qualities, close their ears, and, in compassion, give Him [or Her] help. They will not use words that do not approve of [their Teacher]."
For more specifics on how to comport oneself in the presence of one's Teacher, please see Patrul Rinpoche's Words of My Perfect Teacher. Having practiced the Dharma for more than 45 years with literally scores of Lamas, I can't emphasize too much how important deportment is around one's Teacher. In my experience as a student, even a small adjustment in posture, facial expression, or the tone and manner of speech can reap huge rewards.
Good luck and best wishes.