A lot of actions continue when used once, you can check that with upper/lower body. Tools are the most obvious, but others continue as well like breast fondling, at least until you use your hands for something else. Multiple orgasms are also easier with denial mode, it prevents orgasms for a bit, so you can pile up multiple orgasms easier. Only issue with denial mode is it will often cancel all current actions on the girl, making it difficult to keep up pleasure on multiple body parts. Caress is pretty good to use with denial mode because it hits breasts, clit, mouth at the same time for one action.
That or you can just RNG/brute force your way to a ton of multiple orgasms. If a girl is lewd enough and you're using tools on a girl while fucking her, she'll have multiple body part orgasms enough even without denial mode to eventually reach rank 3 pleasure mark. I never explicitly tried to unlock it and I've gotten the 3rd pleasure mark with a few girls already.
Probably the fastest way to achieve it is to just spam caresses. They use very little energy and you won't have to worry about your vigor, so you can caress most girls for like 5 hours straight and make them orgasm a shit ton.