local Interval = 0
hook.Add("UpdateAnimation", "doing_some_anim", function( ply, velocity, maxseqgroundspeed )

    if CurTime() > Interval then

        local sID, sDur = ply:LookupSequence( "sit" )

        if ply:GetSequence() != sID then
            ply:SetSequence( sID )
        end

        if ply:GetSequence() == sID then
            ply:ResetSequence( ply:GetSequence() )
        end

        Interval = CurTime()+10
    end
end)