Before you feel embarrased by distraction, ask yourself if it is having a detrimental effect on your meeting. If it is not having a bad effect, then do not worry.
If you think that the other person notices it, and does not like it, then you must concentrate on the persons words alone. Repeat what they are saying in your mind so that other things are not distracting you.
Remember, it is normal to lose concentration for many reasons, they can include being tired, being bored by the meeting, or being enchanted by the other person. This is all normal, and with experience, you will be able to disguise your distraction.