whistler said:Grammar abuse aside, let's say you tie up your girlfriend for fun/sex/whatever. She doesn't know about the tickling yet. To start with she must be fine with bondage to agree to it. So you tickle her for a brief moment. So what? She's your girlfriend! She trusts you to tie her up so she'll trust you to respect her wishes if she doesn't want to be tickled.
you should never assume that just because you're in a relationship with someone that you don't need to discuss things like this before you do them. consent should never be assumed.
i'm going to repeat that in boldface. consent should never be assumed.
if someone trusts you enough to let you tie her up she probably trusts you enough to sit down and have a conversation about your feelings and desires.
play safe, people. goddess.