My suggestion is to always build a bridge to their current knowledge or understanding. Perhaps the way EFT is first introduced is important – whether you say it is a relaxation technique, a stress reduction tool or a therapy technique might be useful depending on who is asking.
For some people, they will want to know of the research and how EFT works – it would be highly recommended then to refer to the 100+ published studies, particularly the meta analyses which show EFT has a profound effect for anxiety, depression, and Post Traumatic Stress Disorder. A large effect size in a meta analysis shows that something is really happening and it can be seen with the naked eye. We have the meta analyses and key papers available here to read.
We now have research which shows EFT can down-regulate (switch off) genes associated with the stress response, and can reduce the stress hormone cortisol in the body after one hour of tapping. Brain scans are also showing significantly reduced activation after 4 weeks of EFT (for food cravings in obese adults – our study is here on this site). These trials are published in peer reviewed journals and EFT Universe’s website has links to the articles.
I find language is important to many people, particularly skeptics. Not everyone will relate to the old description that EFT was a ‘meridian based therapy’ which targeted energy systems in the body. We have more solid science now and perhaps a better description would be that EFT is an exposure therapy with a cognitive element, but the part that induces the relaxation response is the somatic tapping on acupoints.
Common evidence based therapies for conditions such as obsessive compulsive disorder, phobias, and anxiety disorders all use an approach that includes exposure and then relaxation (an opposite response to the anxiety feeling). They will often use muscular relaxation and deep breathing during the exposure phase (e.g. someone has a fear of heights and is at the top of a building looking out the window and does the deep breathing while they are there to calm themselves). In EFT, we use the tapping process as the calming response.
Approaching it this way tends to result in EFT not being seen as such a different approach – it fits the current paradigm. Have a read here too http://www.eftuniverse.com/tutorial/building-bridges-from-existing-beliefs-to-eft
My last tip is that if you have a strong reaction yourself to talking with skeptics, or people who question EFT, or even when trying to share how it works, then perhaps using EFT on your own reactions will be useful. I have always found that the calmer I am when a skeptic questions me, the more easily I can access information to share with them that fits their framework.