Sounds weird but it’s pretty straightforward. Lightly tap the fuselage as you board the plane. I was taught to always do this as a gesture of goodwill and respect for the aircraft. My grandfather was an airman who spent much of his time in the Far East and I think the cultural affinity for honor respect etc crap like that really sat with him
anyway Ive had ppl tell me this made them not only feel nice, but safer too. PMA baby (Positive mental attitude)