Take a seat. Because this is BDSM 101. Its better to be physically taught but this will due. Know your soft limits and your hard limits. Soft limits are those that you don't believe you want to do but may eventually be convinced, whereas Hard limits are the things you will NEVER do under any circumstances. These limits are crucial to any Dom /sub relationship. Never enter a BDSM relationship without establishing your limits with the Dom/sub. If at any time you hear your Dom say I don't do limits then it isn't safe to play. There are subs and Dom's who do "no limit" play and you can do it but its best not to due to the potential dangers.
Don't know your limits? Ask your Dom or go online and fill out a BDSM check list then talk to Him/Her about it. Like in many games and acts you can let them test you, tease you, and guide you.
Like in any relationship, Communication is key. I never tell my Dom no and my subs never say no to me. This is because we understand each other and our limits. You can instead explain why this may not be a good idea and understand the Dom may mindfuck with you and threaten to do it anyway but most likely won't. A good Dom "protects the toy" a rule every Dom should live by. Soft limits will often be pushed and encouraged by your Dom. This is natural and its always good to go a smidgen beyond the soft limits and a dash about the hard ones. Not too often because things may get old. Don't be afraid to mix it up and play new games. Make subtle suggestions to your Dom. Say your soft limit is role play. Dress up one night in something a little out of the ordinary or pretend to hide the outfit from the Dom and plant it for them to find. This will go two ways. One, they will know you planned this and punish you for doing so or they will find it and roll with it. BDSM isn't something you do FOR your partner its something you do WITH your partner. If you and it turns you on chances are it will do the same for them as well. This is what i know. My Partner and I in the beginning where strictly vanilla. I'm talking old school. Then I incorporated some not-so-vanilla plans in motion and he has agreed to a few things, even blind folding! So now that we have briefly gone over the basics lets go deeper. No pun intended.