The act of tickling is not a sexual act. The act of inviting someone over to tie them up is. The act of submitting yourself to let another man tie you up is. But most of all said:
It all depends on your definition of "straight," doesn't it. In other cultures - India for example, men often walk together with their arms interlocked. Are they not straight because they do that? Most people define "straight" as heterosexual - that is, the person does not have intercourse with others of the same sex. The key word there is "intercourse." Some people in our culture would even argue that a man can still be straight and still get (not give) blowjobs from other men (I don't think that's true, btw). As the behavior gets more sexually abstract - kissing, touching, etc. - the lines become a little more blurred. Stating emphatically that someone who allows themselves to be tied up and tickled by someone of their own gender is bisexual or gay only expresses one person's passionate opinion - nothing more.
Consider this example of what I'm talking about. In the BDSM community, at public play spaces, there are plenty of very experienced Tops who will play with male or female Bottoms. They may or may not agree to play privately with opposite sex partners, but would never engage in sex with someone of the same sex. Everyone has their own comfort zone - their own line. And that's their own business.
Commenting in a thread like this in order to imply that the OP is bi or gay and to make it clear that you are truly "straight" is nothing more than hijacking a thread. The OP didn't ask what anyone thought of his request, he only asked if anyone was interested in getting together.