Oh if air getting inside is the problem then you need to reduce the stroke height you’ve got as for me I just insert and squeeze out the air and good to go. Only time air gets back in is after I orgasm or get too soft from switching videos or something like that. (Using enough lube helps too, as too little makes it harder for an vacuum seal to occur)
Also then I’ll mention that a few people have put holes it seems into their sleeve to allow air to go out of it: https://discuss.eroscripts.com/chat/c/-/4/53951
But the chrysm sleeve is apparently meant to be one that allows air flow while being close ended so if you don’t want to risk putting too big of an hole in your sleeve and ruining it then you can try this. However I haven’t tried this sleeve so I can’t say if I recommend it or not.
I am of course presuming you aren’t okay with switching to an open ended sleeve nor an lightweight Onahole.
Upscale/FPS increase request topic , Video resolution mega poll and recommended multi-axis script along with single-axis script which is a Fap Hero.