This is actually more the standard interpretation.... jughead is correct actually, it was what was written on wikisocion for ages and personally I like it better than the standard forum interpretation -- which is the more Se you have the "tougher" you are.
That's not how it works, Se is the function of extraverted sensation, experiencing reality directly through sensation. It's a creative and improvisational function. It's focus is on reading an environment for its reality and being very grounded and focused on that reality. Hence they are typically associated with hedonists, habitually indulging in sensation seeking behavior to create some positivity admists their realistic focus. While an INTj is more likely to mentally masturbate to feel a sense of positivity, an Se ego is more likely to indulge in sensations and experiences.
Se's are also more likely to have a non defensive attitude towards reality. Se egos are perfectly fine with looking at reality as it appears without needing to impose some idealistic nonsense over it to make it feel good to them. NT's and NF's get defensive about reality occasionally wanting to impose their intellectual and emotional fantasies and ideals onto reality, trying to kind of shelter themselves from reality and defensively adhering to their idealistic notions. They aren't batshit dumb or retarded fanciful children, they just want to imbue reality with their abstract intuitive notions, which interfere with seeing reality directly as it is.
Finally Se's tend to be experience seeking, since what they are truely after is a positive experience of reality. In order to have this positive experience, they must be non defensive towards reality, instead of living in their heads, they have to live in the moment. This requires them getting adjusted to the negative aspects of reality, they understand to truely experience the positives of reality, they must be open to reality, which means occasionally experiencing the negatives of reality without being sheltered. This of course takes its toll on them much like a sickness, of which their favored course of treating the symptoms is more grounded hedonistic things, because that is what is available to them in this center of focus on reality. Although this hedonism only treats the symptoms, true healing and positive experience from the Se comes from an unrelenting search towards positive experiences in reality.
That's Se... an Se-PoLR is weak in Se along with it being unvalued... a Se-DS is weak as well (important to remember) but it is valued.
So an INFj is too busy with NF matters to be open to experience, but they care little as they prefer Si instead
An INFp is too busy with NF matter to be open to experience, but they care greatly as they prefer to have this NF energy trickle down to reality and experience it directly. This makes a good match for beta STs as their energy wants to occasionally rise above reality into the NF realm, in a way that doesn't seem fake or phony but still connected to direct experience.
INFj's by constrast trickle down to reality in a subjective experiential manner (Si), they want to experience internal sensation, synthasethia like in quality. It's not important about the outward experience but the inward sensation of the experience. I'd probably further go so far as to imply that for the INFj the Si in itself indirectly provides the Se.
Err now to get practical.... the INFj tends to abhor reality, preferring to stay in a zone of comfort, tending to cling onto their NF tendenancy and be defensive towards reality, they aren't after a more real experience they are after an internal sensation in reality, as is the INTj. This defensiveness to reality makes them particularly out of touch with realistic application of force. This is were the instability in their reaction to reality comes from. Like a hyper-reactive defensive person one moment they are fine, almost passive... the next they are batshit defensive and vigilant, maybe not in action but emotionally internally or someform of intense vigilance. If they are forced to react with realistic action the result is the same, disproportionate aggression, or disproportionate passivity.