You need to complete the cycle by placing the tip of your tongue lightly on the roof of your mouth just behind the teeth (where the grooved surface and the smooth surfaces meet). This will allow the energy to clear the head and then flow down the CV Meridian into the dantien or the CV 6 area.
It can be detrimental to allow the energy to rise up and then to not bring it down. This often leads to a condition we call the "running fire" where the qi of the body gets stuck in the head. This can cause headaches, breathing problems, and over time psychological issues. There are two important points, particularly for beginners:
1) Never force the movement of energy in your body. Over time, given proper training, the energy will circulate freely and naturally. Forcing will hinder your progress and may make you sick.
2) After any form of qi gong (tai chi, mediation, etc.) always descend and settle your energy. First you can focus it into the dantien (using the tongue to allow the meridians to connect and the energy to flow downwards) and then simply rub the hands together, rub your arms, face, pat down your back, down the back of your legs, etc. to smooth out any stuck energy. This should be done everytime and is very important.
With regards to the leaning in Tai Chi, the above recommendations will help with this along with proper instruction.