You need to use an indemnification agreement. I have pasted in the language for same below. It is taken from my book, Licensing Photography.
INDEMNIFICATION AGREEMENT
(MODEL) hereby agrees to protect, defend, indemnify, and hold harmless (PHOTOGRAPHER) from and against any and all claims, losses, liabilities, settlements, expenses, and damages, including legal fees and costs (all referred to collectively as “Claims”), which (PHOTOGRAPHER) may suffer or to which (he/she/it) may be subjected for any reason, even if attributable to negligence on the part of (PHOTOGRAPHER) or any other entity, arising out of or related to any act, omission, or occurrence in connection with the creation, production, or use of any image or the performance of any service relating to this Agreement or its subject matter. This provision shall apply to Claims of every sort and nature, whether based on tort, strict liability, personal injury, property damage, contract, defamation, privacy rights, publicity rights, copyrights, or otherwise. (MODEL) assumes all risks, and (his/her/its) obligations under this provision shall survive the performance, termination, or cancellation of this Agreement.
DATE NAME
WITNESS ADDRESS
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Richard Weisgrau
http://www.weisgrau.com
Author of
The Real Business of Photography
The Photographer's Guide to Negotiating
Selling Your Photography
Licensing Photography