Worried the kids might spot that Beckham-esque tattoo or Britney-style belly-button ring?
You might reveal more than you want when you stretch up to the whiteboard.
But, as body art becomes more the norm, is it such a big deal? Should teachers be free to adorn their bodies as long as they don't present health and safety risks? Or, with strict codes for pupils in some schools, should teachers stick to the classic stud in each ear lobe?
Veteran educationist Ted Wragg cautions against tattoos as he believes you may be judged on your body adornment rather than teaching skills. "Some employers will see it as the mark of a trendy permissive, for whom anything goes," says Ted, "which is a pity if you are a sad trad, happiest in white blouse and brogues."
The much tattooed and pierced Neil Dalleywater, editor of Skin Deep, (www.skindeep.co.uk) a monthly magazine devoted to body art, thinks teachers should be ready to defend their body art: "You should be open about your ink, try and bring the interviewer round to your ideas behind the design. Do children really need to be shielded from a practice that is more than 5,000 years old? Could it be a useful talking point in class?"
Jo Lawrie has two tattoos and piercings in her belly button, ears and nose.
A student teacher, she plays down her body art in teaching practice. "I wouldn't wear my nose stud to an interview or more than one pair of earrings," says Jo. "My belly obviously wouldn't be on display and my interview clothes cover up the tattoos."
In the classroom it seems some pupils take body art in their stride.
Leeds PGCE student Paul Slade has an impressive collection of body adornments (nine tattoos and piercings in his nose, tongue, nipples, navel and ears) but manages to hide them at school by wearing long-sleeved shirts.
But the world caught a glimpse of his ink in the school panto when Paul wore a T-shirt. "The kids obviously noticed, but noone said anything," said Paul. "The only person who mentioned them was the head of music who said how nice they were."
Occasionally the kids get nosy. Paul says: "They spot the tongue piercing and ask questions. I just say that now isn't the time to talk about it. One kid told me he wanted to grow his hair long and have piercings and tattoos like me. I said 'OK but wait until you are 18'."
What employers think We asked three teacher recruitment agencies for their views on tattoos and piercings.
Emma Mydat, Academics Ltd I would mention it at interview, especially if it's a piercing in the mouth. I'd advise any of our teachers to dress conservatively until you've been at the school a couple of weeks and then you can judge what's acceptable.
Nathan Chisholm, ITN Teachers I've worked with three schools in London, two primary and one secondary, where teachers are not allowed visible tattoos or piercings. I also know of one teacher who resigned from a new contract because of school management pressure to remove an eyebrow piercing.
Dave Goodwin, SOS Education We have had comments, rather than complaints, from a school asking us to instruct a teacher not to wear an eyebrow piercing.
"So we sent a memo to our staff that said "visible piercings should be removed if they contravened a school's dress code.
COLOUR ME BEAUTIFUL
*The Prince of Wales sparked a fashion for Victorian toffs to have tattoos when, in 1862, he had a Jerusalem Cross tattooed on his arm.
* The most popular tattoos are Japanese, tribal and Celtic designs, dolphins, butterflies, roses or a person's name.
* According to the Journal of Dermatology, up to 75 per cent regret having a tattoo and seek advice on having it removed on average 14 years later.
* Even Barbie has a tattoo. The 1999 incarnation of the doll had a butterfly tattoo on her stomach.
* In the US an estimated one in 10 adults are tattooed.