Pīti😁 sā-misā (worldly, carnal)

Rapture, mental thrill, excitement derived from worldly pleasures like food, sex, etc.

Pīti😁 nirā-misā (unworldly, non carnal, spiritual)

0. Note Pīti😁 in first and second jhāna, and 7sb☀️ → 4😁 (fourth of 7 awakening factors), are exactly the same. They're both nirā-misā (unworldly, non carnal) rapture (SN 46.3).
1. the “default” option the Buddha expects us to use as a pīti generator on demand, comes from the prior 7sb factor “vīriya-sam-bojjhanga”. In short, it’s because viriya is doing a good job of purifying our mind and behavior, the uplifting mental emotion of rapture/pīti and pamojja (mudita) arise from reflecting in ourselves that our sīla and virtue are pure, so we can train all day and night enraptured.
2. Pīti😁 caused by 7sb☀️ → 1🐘 sati-bojjhanga deliberately choosing a particular Dhamma topic to recollect and feed into the 7sb samadhi engine. The topic would be appropriate to the needs of the immediate moment. But pretty much any Dhamma topic should cause rapture to arise, because you know your dukkha💩 is about to be lessened by applying that Dharma, right away. It’s just like an addict getting an endorphine rush before they even consume the physical or mental food. The mere thought anticipating the pleasurable result that's about to happen triggers the pleasure chemicals in the brain before 'contact' with the source actually happens. Similarly, if you’re not dense, eventually you can tap into the same biochemical process of cue/trigger, routine/habit, reward (brain chemical high) by paying attention to the nimitta or perception that any genuine Dharma is beautiful, not just aesthetically, but because it pays cold hard cash and delivers results in immediate relief from Dukkha.
3. Other causes of Pīti😁 would be combinations, subsets, and slight variations of category 1 and 2, such piti caused by encountering inspiring figures in the sangha, such as the Buddha and arahants, especially an inspiring Dhamma teacher delivering a live Dhamma talk. Delighting in virtue of your companions in the holy life, and good Dhamma friends, even just seeing their presence or thinking about them (SN 46.3).
4. spontaneous Pīti😁 and jhāna can just suddenly hit you like a hurricane whereby you enter jhāna by pacifying (passaddhi-bojjhanga) the body and mind, and the hydraulic sensation and/or electrical orgasmic fireworks can suddenly hit you. The moment right before, the mind was completely ordinary, and did not deliberately choose a Dhamma topic with which to be inspired by.

✅Right and ⛔Wrong

✅ in case #4, even though one did not intentionally direct the mind toward an inspiring Dhamma topic, or reflect on one's virtue (cases 1-3), the pīti is a result of one's long term virtuous and effective practice. That cumulative practice sowed the seeds for seemingly spontaneous jhāna and pīti to occur.
⛔ Late Theravada propaganda redefined jhāna into a pure samatha vehicle (divorced from vipassana) and explains case #4 being the result of forcing the mind into "one-pointedness", leading to a supression of 5 hindrances. This is likely of heterodox origin, and goes completely against the grain of EBT, which emphasizes the union of samatha and vipassana within jhāna, and development of pīti and insight using 7sb holistically and organically, in conjunction with vipassana while in the 4 jhānas.
⛔ contrary to EBT case 0 stated above (pīti of jhāna is exactly the same as pīti-sambojjhanga of 7sb), Late Theravada claims they are different (♾️🦆 infinite duck fallacy). They try to sabotage 7sb awakening factors by creating a 5 jhāna factor system to replace 7sb as the natural counterpart to 5niv hindrances.