Clark rubs up and down on the vertical position of my hand when I'm...well (you asked for info) peeing... and my hand is against the wall....I'm not sure if it's attention getting or sexual...I'd easily concede it's sexual.....but it's only for about a minute so I just talk to him and ask "what are you doing" and really just kind of use it to "bond back" without the possibly sexual overtones he'd like.
On my shoulder he never does this, so thats why I'm undecided 100%. Some part of my interaction with him for in the wider scope makes me think it's something he figured out gets attention....so I dunno. But I don't think it's harmful, nor do I feel I need to stop the behavior...it's not even rhythmic, it's more of a random....touching you with my side butt or hip kind of thing....I'd maybe consider it more a dominance move....but I have no idea what the crap goes on in his head other than the things he can obviously confer to me like I want juice, I want strawberry, I wanna play fight, I wanna kissy stuff.